MSc (Physics) / Department of Physics / Currently the dye sensitized solar cells have attracted more attention due to their low cost, transparency and flexibility. These types of solar cells use the dye molecule adsorbed on TiO2 semiconductor in Nano architecture with the role of absorbing photons, in recent research attempts are being made to shifts the absorption spectral of TiO2 to visible and near infrared–region of solar spectrum to achieve maximum photo absorption which yields to an increase in the efficiency of the dye sensitized solar cells. In the current study, density functional theory (DFT) was used to model two croconate dyes (CR1 and CR2), one with an electron donating methyl group (CR1) and the other with an electron –withdrawing caboxyl group (CR2). The geometric, electronic and optical properties of these dyes were compared. The adsorption behaviour of the two dyes on (010 and 100) anatase TiO2 surfaces were investigated in this study by employing first principle calculation based on DFT using a plane-wave pseudo potential method. The generalized gradient approximation (GGA) was used in the scheme of Perdew-Burke Ernzerhof to describe the exchange -correlation function as implemented in the CASTEP package in Material Studio of BIOVIA. The adsorption results shows a spontaneous electron injection followed by efficient regeneration of the oxidized dye molecules by the electrolyte and strong binding ability of CR2 to the TiO2 surface, but also shows a comparable binding strength of CR1. The results of this study will help in the design of high efficient dye for DSSCs. / NRF

AN ABSTRACT OF THE DISSERTATION OFLaith A. Zeinaldeen, for the Doctor of Philosophy degree in AGRICULTURAL SCIENCES – Renewable Energy, presented on November 2, 2020, at Southern Illinois University Carbondale.TITLE: ESTIMATING THE PERFORMANCE OF HYBRID (MONOCRYSTALLINE PV - COOLING) SYSTEM USING DIFFERENT FACTORSMAJOR PROFESSOR: Dr. Logan O. ParkAmbient temperature significantly affects photovoltaic (PV) panel performance. High temperature reduces PV panel efficiency, fill factor, and maximum power, driving up solar electrical system investment return period by increasing startup cost. Using a proper cooling system to cool down the PV panel temperature, especially during the summer season, will improve the PV panel performance, enhance its longevity, and accelerate the startup cost recovery to the solar electrical system. This dissertation presents two studies about monocrystalline PV panels. The studies used two general objectives: (i) study the best cooling period and water nozzle type to improve the monocrystalline PV panel output; and (ii) evaluating the performance of the monocrystalline PV panel using different cooling systems, other water pump discharge, and various water types during different times of day. In the first study (chapter 4), an experiment was conducted during July 2018 to determine Effect of using different cooling periods and different water nozzle types on the fill factor, efficiency, and the maximum power of monocrystalline PV panel. This experiment used two factors. The first factor was the cooling periods, which included three levels of PV panel cooling periods (5, 15, and 30 minutes). The second factor was water nozzle type: hollow cone and flat fan.In the second study (chapters 5, 6, and 7), an experiment was conducted during July and August 2018 to determine Effect of using different factors on the performance of monocrystalline PV panel at a site belong to the College of Agriculture – Southern Illinois University in Carbondale, IL. This experiment used four factors. The first factor was the time of day, the second factor was the cooling system, the third factor was the water pump discharge, and the fourth factor was the water type. The present studies' principal findings were: (i) the first experiment, the 15 minutes cooling period achieved the highest PV panel fill factor (0.795). In comparison, the 30 minutes cooling period reached the highest panel efficiency (18.6%) and maximum power (92.5 Watt). In contrast, the 5 minutes cooling period achieved the lowest PV panel fill factor (0.720), lowest panel efficiency (12.9%), and most insufficient panel maximum power (63.5 Watt). The hollow cone water nozzle achieved the highest panel fill factor (0.783), highest panel efficiency (16.60%), and the most elevated PV panel maximum power (82.8Watt). Interaction between the cooling and water nozzle types was non-significant on PV panel fill factor, significant on panel efficiency, and highly significant on PV panel maximum power. The interaction results between the cooling period and nozzle type demonstrate that the hollow cone nozzle with 30 minutes cooling period achieved the highest panel fill factor, highest panel efficiency, and the most elevated panel maximum power. The flat fan with a 5-minute cooling period achieved the lowest fill factor, lowest panel efficiency, and most insufficient panel maximum power. Tukey test results showed a highly significant difference (P < 0.0001) between the cooling period and the control treatment, and between the nozzle type treatment and the control treatment on panel fill factor, efficiency, and panel maximum power. Cooling periods have the most considerable effect on panel fill factor, panel efficiency, and maximum panel power, followed by the nozzle type. (ii) The second experiment results showed, the first cooling system (HC1) achieved the highest PV panel maximum power (77.0Watt), highest fill factor (0.745), highest PV panel efficiency (14.75%), highest average net energy (39.5Wh), highest PV panel energy (189.0 Wh) and highest average power gain (34.6Watt) comparing to the rest of the cooling systems. In comparison, the fourth (FtF2) achieved the lowest maximum power (58.0 Watt), lowest fill factor (0.653), lowest average efficiency (11.6%), lowest average net energy (-4.0Wh), lowest average energy (147.5Wh), and lowest average power gain (17.5 Watt). The fifth cooling system (SP) achieved the least average water consumption (2.0 L / hr.), while the second cooling system (HC2) achieved the highest average water consumption (39.0 L / hr.). The medium water pump discharge (M) produced the most elevated PV panel maximum power (67.6 Watt), highest fill factor (0.709), highest average PV panel efficiency (13.28%), highest average PV panel net energy (18 Wh), highest average PV panel energy (169.0Wh) and the highest average PV panel power gain (25.9Watt). High water pump discharge (H) achieved the lowest maximum power (63.8Watt), lowest average panel efficiency (12.48%), lowest average net energy (7.5Wh), lowest average panel energy (159.5Wh), and the lowest average power gain (21.8 Watt). The low water pump discharge (L) achieved the lowest panel fill factor (0.698). Lake water achieved the highest panel maximum power (66.1Watt), lowest PV panel fill factor (0.698), highest panel efficiency (12.94%), lowest net energy (12.8 Wh), highest panel energy (165.2 Wh), and lowest power gain (23.5Watt). In contrast, city water achieved the most elevated PV panel fill factor (0.708), most insufficient panel maximum power (64.8 Watt), highest average PV panel net energy (14.8 Wh), lowest efficiency (12.62%), highest average PV panel power gain (24.25 Watt) and lowest panel energy (162.1 Wh). Tukey post hoc difference testing showed highly significant differences (P < 0.0001) between the time of day, cooling system, water pump discharge, water type treatments, and their control treatment on PV panel maximum power, fill factor, panel efficiency, panel net energy, panel energy, power gain, and the system water consumption. The cooling system has the most considerable effect on PV panel maximum power, panel fill factor, panel efficiency, panel net energy, panel energy, panel power gain, and the system water consumption. In general, using the cooling system improves the PV panel performance through enhancing the PV panel efficiency, maximum panel power, panel fill factor, panel net energy, panel energy, and PV panel power gain. Keywords: Cooling system, cooling periods, water pump discharge, water type, time of day, efficiency, maximum power, fill factor, net energy, panel energy, PV panel power gain, and cooling system water consumption.

Hybrid organic-inorganic perovskites has attracted much attention for its diverse optoelectronic applications. Many studies point out that hybrid organic-inorganic perovskites compounds have superior physical properties that can enable these materials to fabricate good performance solar cells. However, there is a lack of repeatable recipe for the fabrication of perovskite transistors with high mobilities. In this work, a detailed investigation has been conducted on the fabrication of Methylammonium-based perovskite compounds transistors on various polymer substrates. A group of methacrylate-based polymers has been chosen as the materials for gate dielectric layers. Generally, we found that the growth of perovskite crystals highly depends on the hydrophobicity of the substrates. More hydrophobic polymer layers yield larger crystal growth, but suppress the adhesion of perovskites crystals. Aromatic groups in methacrylate-based polymers have hydrophobic properties but it still gives better compact perovskite films with larger crystals. Poly(phenyl methacrylate) (PPhMA) enables the growth of the best perovskite films. The best performance of MAPbI3-xClx perovskite transistors was fabricated on PPhMA with an electron mobility µsat = 4.30 cm2 V−1 s−1 at 150 K. Photothermal deflection spectroscopy was used to investigate the subgap optical absorptions of the perovskite films.

The aim of this research is to design the communications monitoring and control functionalities of an energy-efficient, scalable system, capable of supporting robotic cleaning and fault detection of photovoltaic panels, deployed in solar electric power generation plants. The communication functionality is implemented by using a wireless sensor network (WSN) deployed over the photovoltaic energy production plant’s area. The network is designed to support the communication needs of static-sensing nodes as well as moving robotic units. It transports sensing data and commands between end units and the monitoring and control entity of the electric energy generation plant. Having robotic units replace humans in the cleaning and inspection tasks not only reduces the operational cost of the plant, but also results in increased energy production. Several innovations were necessary to achieve our objective, which are presented in this dissertation. A working prototype of the cleaning robotic system was built and tested in a solar power plant for a duration of 6 month. The prototyping was done in collaboration of Tipot technology.

Organic photovoltaic (OPV) devices utilizing organic (carbon-based) semiconductors have maintained research interest due to their potential for inexpensive, non-toxic, flexible, and lightweight solar modules. Numerous organic polymers and small molecules have been investigated for OPV applications, however a focus on maximizing the power conversion efficiency (PCE) of lab-scale devices has generated many novel active materials that are too complex to be realistically synthesized on a commercial scale. It has become apparent that developing low-cost, scalable, and stable active materials is crucial for the commercialization of OPV devices. Metal phthalocyanines (MPcs) are a well-known family of molecules with established scale up chemistry from their use as colorants and have demonstrated strong performance as low-cost semiconductors in organic electronic devices. However, their potential in solution-processed OPV devices has not been fully realized. In this thesis, a series of materials based on silicon phthalocyanine (SiPc) and tin phthalocyanine (SnPc) were synthesized and characterized. Novel molecular designs and OPV device architectures were investigated to further establish the use MPcs as low-cost active materials and to probe new applications. Specifically, the chemical and physical differences of structurally analogous soluble SiPc and SnPc derivatives were examined for the first time. The ability of a SiPc derivative to act as a thermal crosslinker to stabilize active layer morphology while simultaneously contributing to photocurrent generation was also proven. SiPc derivatives were then studied as electron acceptors paired with P3HT and PBDB-T donor polymers, achieving a PCE up to 4.3 %. The results herein establish new potential roles for group 14 MPcs in OPV devices while also demonstrating their synthetic simplicity and versatility. This work also serves as a basis for the wealth of chemical functionalization which remains available for continued optimization of these materials.

The development of nonfullerene organic solar cells (OSCs) has attracted increasing interests because of the intrinsic advantages of nonfullerene acceptors, including their high absorption capability over the long wavelength region, tunable electronic properties, and excellent miscibility with polymer donors. Recently, power conversion efficiency (PCE) of >15 % for single-junction nonfullerene OSCs has been reported. Apart from the rapid progresses made in the cell efficiency, significant improvement in the stability of nonfullerene OSCs is required if the organic photovoltaic technology is to become a viable option for commercialization. The lifetime of OSCs is closely related to the intrinsic properties of the functional photoactive materials, e.g., the acceptors with suitable energy levels, morphology of bulk heterojunction (BHJ), formation of the active layer, interlayer engineering and device configuration. However, the comprehensive study of the impacts of the morphological properties and vertical phase separation in a BHJ on charge transport, built-in potential, charge recombination processes, PCE as well as the lifetime of nonfullerene OSCs has not been reported yet. This work has been focused on unraveling the stability of highly efficient OSCs using different nonfullerene acceptor/polymer blend systems, e.g., 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis (4-hexylphenyl)-dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene (ITIC): poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)] (PTB7-Th), ITIC:poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl) -benzo[1,2-b:4,5- b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4', 5'-c'] dithiophene-4,8-dione)] (PBDB-T), and 3,9-bis(2-methylene-((3-(1,1 -dicyanomethylene)-6,7-difluoro)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene(IT-4F):poly[(2,6-(4,8-bis(5-(2-ethylhexyl)-4-fluorothiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione)] (PBDB-T-2F). The lifetime of the nonfullerene OSCs has been analyzed systematically using a combination of morphology, photoelectron spectroscopy, light intensity-dependent current density-voltage measurements, transient photocurrent and aging studies. The effects of built-in potential (V0), charge extraction, and bimolecular recombination processes on the performance and stability of nonfullerene OSCs with regular and reverse configurations were studied. The results reveal that PTB7-Th:ITIC based OSCs with a reverse configuration are more favorable for efficient operation, due to the advantages of: (1) enhancement of charge collection by avoiding the holes passing through acceptor-rich region, which would otherwise occur in an OSC with a regular configuration, and (2) suppression of bimolecular recombination enabled by a higher V0. It shows that the PTB7-Th:ITIC based OSCs with a reverse configuration possess a slow degradation process, and >29% increase in PCE (8%) as compared to that of an optimized control OSC (6.1%). We found that a gradual decrease in V0 and hence the performance deterioration in the regular configuration PBDB-T:ITIC OSCs are caused mainly by the interfacial reaction between nonfullerene acceptor (ITIC) and poly(3,4-ethylenedioxythiophene) -poly(styrenesulfonate) (PEDOT:PSS) hole transporting layer (HTL). The reduction in V0, due to the unavoidable interfacial reaction between ITIC and PEDOT:PSS at the BHJ/HTL interface in the OSCs, can be overcome through interfacial engineering, , e.g., introducing a thin molybdenum oxide (MoO3) passivation layer. The effect of the HTL on stability of PBDB-T:IT-4F based OSCs has been analyzed using different HTLs, e.g., a pristine PEDOT:PSS layer, a MoO3-doped PEDOT:PSS layer and a pure MoO3 layer. It shows that MoO3-induced oxidation doping of PEDOT:PSS favors the stable and efficient operation of nonfullerene OSCs. The results suggest that a stable and high V0 across the BHJ is a prerequisite for attaining high efficiency nonfullerene OSCs with long-term stability.

Bulk heterojunction organic solar cells (BHJ OSCs) have been fascinated in recent years for the future green energy generation due to their most promising results of low-cost fabrication, great flexibility, and lightweight properties. Very recently small molecule donors in the BHJ active layers have shown prominent attention due to the synergistic advantages over the polymer counterparts, which possess easy purification, highly facile synthesis, and negligible batch-batch variations. To construct push-pull molecules for p-type semiconductors, acceptor-donor-acceptor (A-D-A) based backbone exalted so far. In addition, the most impressive small molecule electron-donor units (D) are like benzodithiophene (BDT), oligothiophene, 3-dithienosilole (DTS), and indacenedithiophene (IDT) and so on. Likewise, electron-acceptors (A), such as 3-alkylrhodanine, diketopyrrolopyrrole (DPP), and perylenediimide (PDI) have been utilized. Porphyrin derivatives show excellent photochemical and electrochemical properties. Interestingly, porphyrins can be easily modified by different substituents at the peripheral positions (meso- and β-) and metal insertions at the center of the porphyrin core. In this work, we design, synthesize and characterize visible-near infrared absorbing new porphyrin dimer based small molecules with acceptor-donor-acceptor (A-D-A) configuration for bulk heterojunction organic solar cells, and investigate their structure-property relationships, specifically the effect of conjugation and planarity of the backbone central units on the charge mobility, film morphology, and solar cell performances. Chapter 1 deals with an overview of the past and recent development of BHJ OSCs, particularly the key principles and photovoltaic characteristics. Furthermore, we focus on the detailed classification of porphyrin-based small molecules and their performances in OSCs. In chapter 2, two promising near-IR absorbing porphyrin-based dimeric small molecules were designed and synthesized, in which diketopyrrolopyrrole-ethynylene-bridged porphyrin dimers are capped with electron-deficient 3-ethylrhodanine (A2) via a π-bridge of phenylene ethynylene, with an optimal A2-π-D-A1-D-π-A2 architecture affording porphyrin dimers DPP-2TTP and DPP-2TP. They possess strong absorption in ranges of 400-550 (Soret bands) and 700-900 nm (Q bands). Their intrinsic absorption deficiency between the Soret and Q bands could be perfectly compensated by a wide bandgap small molecule DR3TBDTTF with absorption in 500-700 nm. Impressively, the optimal ternary device based on the blend films of DPP-2TPP, DR3TBDTTF (20 wt.%) and PC71BM, shows a PCE of 11.15%, while the binary devices based on DPP-2TTP/PC71BM and DPP-2TP/PC71BM blend films exhibit PCEs of 9.30% and 8.23%, respectively. The high compatibility of the low bandgap porphyrin dimers with the wide bandgap small molecule provides a new threesome with PC71BM for highly efficient panchromatic ternary organic solar cells. Chapter 3 describes another two new A-π-D-π-A structural porphyrin small molecules denoted as TDPP-2P and TDPPE-2P which are constructed from dimeric porphyrin linked by 2,5-bis(2-butyloctyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (TDPP), and 2,5-bis(2-butyloctyl)-3,6-bis(5-ethynyl-2-thienyl)-2,5-dihydro-pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (TDPPE), respectively, further π-extended symmetrically with electron-deficient 4-[(3-ethyl-4-oxo-2-thioxo-5-thiazolidinylidene)methyl]-phenylethynyl fragments. Compared to the absorption spectra of TDPP-2P, astonishingly TDPPE-2P improves the range of near-infrared over 1000 nm due to the enhanced coplanarity of the central core. Moreover, the intrinsic absorption deficiency (500-700 nm) is perfectly compensated by IT-M small molecule acceptor. Remarkably the blend film TDPPE-2P:IT-M accomplished panchromatic photo-current absorption from 400-900 nm, as a result, the device exhibits a prominent PCE of 5.69%. Whereas, the film TDPP-2P:IT-M shows comparatively low PCE of 4.12%. Finally, we believe that such a combination of TDPPE-2P:IT-M device demonstrates synergetic compatibility of donor/acceptor domain to promote the complementary absorption spectrum and enhances through higher hole mobilities and better crystallinity of the surface and interface for non-fullerene small-molecule organic solar cells. In Chapter 4, we further modified and synthesized a new series of A*-π-D2-D1-D2-π-A* based porphyrin dimer (2P) (D2) small molecules flanked by 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-2,6-diethynylbenzo[1,2-b:4,5-b']dithiophene (TBDTE) and 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene (TBDT) as TBDTE-2P and TBDT-2P respectively, in which benzodithiophene (BDT) (D1) based analog was constructed as a central unit because of extended coplanarity conjugation length. Finally, TBDTE and TBDT units end-capped with 3-ethylrhodanine (A*) via a π-bridge of phenyl ethynyl linker and 2-octyldodecan-1-al long alkyl chain was used on vertical meso-porphyrins to improve the material solubility for the solution-processed OSCs. The compound TBDTE-2P accomplishes absorption range from 400-800 nm in the vis-near-infrared region, whereas TBDT-2P compound absorbs 400-700 nm range. The higher absorption range of TBDTE-2P arises from more planar backbone orientation and strong intramolecular charge transfer (ICT) within the donor molecules. Further, we focus on the OPV performances of binary devices TBDTE-2P / TBDT-2P: IDIC under AM 1.5G 1-Sun and 300 lux LED illuminations. The champion device TBDTE-2P: IDIC was accumulated a PCE of 7.46% under 1-Sun whereas a PCE of 12.34% was obtained under indoor light illuminations. The exploit of superior properties, charge generation and collection, hole and electron mobilities, and atomic force microscopy (AFM) were also examined. In Chapter 5, we synergistically designed and synthesized two new porphyrin dimers triply fused at meso-meso, β-β and βꞌ-βꞌ positions, from the corresponding meso-meso singly-linked porphyrin arrays. These fused porphyrin tapes differ by two metal atoms at the porphyrin core, such as zinc and nickel, termed as F-C19ZnP and F-C19NiP, respectively. With the purpose for design new acceptor-donor-acceptor small molecules for OSCs, the two fused porphyrin tapes were investigated in detail on the photophysical and electrochemical properties. Both fused porphyrins exhibit a strong and wide Soret-band absorption from 400-570 nm. Interestingly, the compound F-C19ZnP is recorded a larger red-shift absorption than the compound F-C19NiP consistent with cyclic voltammetry (CV) measurements, because the Zn-porphyrin attains more planar conjugated geometry. Finally, the dissertation was completed with a summary in chapter 6

Bulk heterojunction organic solar cells (BHJ OSCs) have been fascinated in recent years for the future green energy generation due to their most promising results of low-cost fabrication, great flexibility, and lightweight properties. Very recently small molecule donors in the BHJ active layers have shown prominent attention due to the synergistic advantages over the polymer counterparts, which possess easy purification, highly facile synthesis, and negligible batch-batch variations. To construct push-pull molecules for p-type semiconductors, acceptor-donor-acceptor (A-D-A) based backbone exalted so far. In addition, the most impressive small molecule electron-donor units (D) are like benzodithiophene (BDT), oligothiophene, 3-dithienosilole (DTS), and indacenedithiophene (IDT) and so on. Likewise, electron-acceptors (A), such as 3-alkylrhodanine, diketopyrrolopyrrole (DPP), and perylenediimide (PDI) have been utilized. Porphyrin derivatives show excellent photochemical and electrochemical properties. Interestingly, porphyrins can be easily modified by different substituents at the peripheral positions (meso- and β-) and metal insertions at the center of the porphyrin core. In this work, we design, synthesize and characterize visible-near infrared absorbing new porphyrin dimer based small molecules with acceptor-donor-acceptor (A-D-A) configuration for bulk heterojunction organic solar cells, and investigate their structure-property relationships, specifically the effect of conjugation and planarity of the backbone central units on the charge mobility, film morphology, and solar cell performances. Chapter 1 deals with an overview of the past and recent development of BHJ OSCs, particularly the key principles and photovoltaic characteristics. Furthermore, we focus on the detailed classification of porphyrin-based small molecules and their performances in OSCs. In chapter 2, two promising near-IR absorbing porphyrin-based dimeric small molecules were designed and synthesized, in which diketopyrrolopyrrole-ethynylene-bridged porphyrin dimers are capped with electron-deficient 3-ethylrhodanine (A2) via a π-bridge of phenylene ethynylene, with an optimal A2-π-D-A1-D-π-A2 architecture affording porphyrin dimers DPP-2TTP and DPP-2TP. They possess strong absorption in ranges of 400-550 (Soret bands) and 700-900 nm (Q bands). Their intrinsic absorption deficiency between the Soret and Q bands could be perfectly compensated by a wide bandgap small molecule DR3TBDTTF with absorption in 500-700 nm. Impressively, the optimal ternary device based on the blend films of DPP-2TPP, DR3TBDTTF (20 wt.%) and PC71BM, shows a PCE of 11.15%, while the binary devices based on DPP-2TTP/PC71BM and DPP-2TP/PC71BM blend films exhibit PCEs of 9.30% and 8.23%, respectively. The high compatibility of the low bandgap porphyrin dimers with the wide bandgap small molecule provides a new threesome with PC71BM for highly efficient panchromatic ternary organic solar cells. Chapter 3 describes another two new A-π-D-π-A structural porphyrin small molecules denoted as TDPP-2P and TDPPE-2P which are constructed from dimeric porphyrin linked by 2,5-bis(2-butyloctyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (TDPP), and 2,5-bis(2-butyloctyl)-3,6-bis(5-ethynyl-2-thienyl)-2,5-dihydro-pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (TDPPE), respectively, further π-extended symmetrically with electron-deficient 4-[(3-ethyl-4-oxo-2-thioxo-5-thiazolidinylidene)methyl]-phenylethynyl fragments. Compared to the absorption spectra of TDPP-2P, astonishingly TDPPE-2P improves the range of near-infrared over 1000 nm due to the enhanced coplanarity of the central core. Moreover, the intrinsic absorption deficiency (500-700 nm) is perfectly compensated by IT-M small molecule acceptor. Remarkably the blend film TDPPE-2P:IT-M accomplished panchromatic photo-current absorption from 400-900 nm, as a result, the device exhibits a prominent PCE of 5.69%. Whereas, the film TDPP-2P:IT-M shows comparatively low PCE of 4.12%. Finally, we believe that such a combination of TDPPE-2P:IT-M device demonstrates synergetic compatibility of donor/acceptor domain to promote the complementary absorption spectrum and enhances through higher hole mobilities and better crystallinity of the surface and interface for non-fullerene small-molecule organic solar cells. In Chapter 4, we further modified and synthesized a new series of A*-π-D2-D1-D2-π-A* based porphyrin dimer (2P) (D2) small molecules flanked by 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-2,6-diethynylbenzo[1,2-b:4,5-b']dithiophene (TBDTE) and 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene (TBDT) as TBDTE-2P and TBDT-2P respectively, in which benzodithiophene (BDT) (D1) based analog was constructed as a central unit because of extended coplanarity conjugation length. Finally, TBDTE and TBDT units end-capped with 3-ethylrhodanine (A*) via a π-bridge of phenyl ethynyl linker and 2-octyldodecan-1-al long alkyl chain was used on vertical meso-porphyrins to improve the material solubility for the solution-processed OSCs. The compound TBDTE-2P accomplishes absorption range from 400-800 nm in the vis-near-infrared region, whereas TBDT-2P compound absorbs 400-700 nm range. The higher absorption range of TBDTE-2P arises from more planar backbone orientation and strong intramolecular charge transfer (ICT) within the donor molecules. Further, we focus on the OPV performances of binary devices TBDTE-2P / TBDT-2P: IDIC under AM 1.5G 1-Sun and 300 lux LED illuminations. The champion device TBDTE-2P: IDIC was accumulated a PCE of 7.46% under 1-Sun whereas a PCE of 12.34% was obtained under indoor light illuminations. The exploit of superior properties, charge generation and collection, hole and electron mobilities, and atomic force microscopy (AFM) were also examined. In Chapter 5, we synergistically designed and synthesized two new porphyrin dimers triply fused at meso-meso, β-β and βꞌ-βꞌ positions, from the corresponding meso-meso singly-linked porphyrin arrays. These fused porphyrin tapes differ by two metal atoms at the porphyrin core, such as zinc and nickel, termed as F-C19ZnP and F-C19NiP, respectively. With the purpose for design new acceptor-donor-acceptor small molecules for OSCs, the two fused porphyrin tapes were investigated in detail on the photophysical and electrochemical properties. Both fused porphyrins exhibit a strong and wide Soret-band absorption from 400-570 nm. Interestingly, the compound F-C19ZnP is recorded a larger red-shift absorption than the compound F-C19NiP consistent with cyclic voltammetry (CV) measurements, because the Zn-porphyrin attains more planar conjugated geometry. Finally, the dissertation was completed with a summary in chapter 6

This work shows a laboratory based demonstration that elastic scattering from a layer of wavelength-sized particles can be used to concentrate sunlight for use in photovoltaic power production. The concentrator design consists of a layer of particles dispersed across a mirrored glass plate. Photovoltaic cells line the edges of the plate, which receive light that is coupled into the plate via scattering by the particles and confined thereafter by total internal reflection. All materials used to construct the concentrator are low-cost off-the-shelf items typically available at hardware stores. The net power produced is compared to a single, bare cell that is directly illuminated by the same light source. This comparison shows a promising trend in terms of overall concentrator size that may eventually yield a concentrator capable of producing more power than that produced by the same amount of cell material under direct illumination.

The entire contiguous United States experienced a solar eclipse on August 21st, 2017 which passed from the Pacific to the Atlantic Coasts. The path of totality crossed 14 states while other states had partial eclipse. Due to the rarity of this event, it was known as “The Great American Eclipse” and NASA collaborated with 52 universities across the United States to launch weather balloon payloads to record this impactful event. Although Montana State University designed a workshop for all universities involved in order to assist those not experienced in the area, Mississippi State University decided to design our own payload. Our system was designed in order to meet the standards of a 2U CubeSat. One key aspect of our payload is that it is entirely made from 3D printed parts with over 100 prototype parts made over the length of two years. Instead of buying an off the shelf flight computer, we designed and built a custom Hexa-Processor Computer Board which gave us flexibility with the computation needs. A turret was also developed that housed two cameras and could spin 360 degrees, allowing it to counter act the rotations of the payload in order to obtain a stabilized image. The payload was launched in Kentucky and was a successful flight without any damages to the payload.