Philosophiae Doctor - PhD / The commercial need to improve the performance of low-cost organic solar cells has led to the idea for this research. The study discusses the synthesis of one dimensional TiO2 and ZnO nanowire arrays synthesised using a hydrothermal autoclave method and their application in bulk heterojunction inverted organic solar cells. Previous literature has shown that the precise manipulation, positioning and assembly of 1D nanostructures remain one of the greatest challenges in the field of nanotechnology, with much of the difficulty arising primarily from the lack of size and scale of the materials as well as the inability to visualise the nanostructures. In particular, one dimensional metal-oxides such as TiO2, ZnO and Fe2O3 have emerged as attractive alternatives to traditional semiconductor structures such as Si and GaAs as they are simple and inexpensive to manufacture, with research showing that application of ZnO nano-cones yield efficiencies of 8.4%, which is very attractive given the scope that exists in optimising the metal-oxide architecture. Much is still to be learned from the precise structural features of these materials and their influence on device performance. In this regard, this work largely focuses on this aspect of metal-oxide nanowires prior their application in organic solar cells.

With power conversion efficiency surpassing the 10% milestone for commercialization, photovoltaic technology based on solution-processable polymer solar cells (PSCs) provides a promising route towards a cost-efficient strategy to address the ever-increasing worldwide energy demands. However, to make PSCs successful, challenges such as insufficient light absorption, high maintenance costs, and relatively high production costs must be addressed. As solutions to some of these problems, the unique properties of nanostructured materials and complimentary light absorption in multi-junction device structure could prove to be highly beneficial. As a starting point, integrating nanostructure-based transparent self-cleaning surfaces in PSCs was investigated first. By controlling the length of the hydrothermally grown ZnO nanorods and covering their surface with a thin layer of chemical vapor-deposited SiO2, a highly transparent and UV-resistant superhydrophobic surface was constructed. Integrating the transparent superhydrophobic surface in a PSC shows minimal impact on the figure of merit of the PSC. To address the low mechanical durability of the transparent superhydrophobic surface based on SiO2-coated ZnO nanorods, a novel method inspired by the water condensation process was developed. This method involved directly growing hollow silica half-nanospheres on the substrate through the condensation of water in the presence of a silica precursor. Benefit from the decreased back scattering efficiency and increased light transport mean free path arise from the hollow nature, a transparent superhydrophobic surface was realized using submicrometer sized silica half-nanospheres. The decent mechanical property of silica and the “direct-grown” protocol are expected to impart improved mechanical durability to the transparent superhydrophobic surface. Regarding the application of multi-junction device structure in PSCs, homo multi-junction PSCs were constructed from an identical polymer absorber, in which the homo-tandem device showed an enhanced power conversion efficiency (PCE) (8.3% vs 7.7%) relative to the optimized single junction PSC. The high open voltage (>1.8 V) achieved in homo-tandem PSCs allowed for water splitting with an estimated solar-to-fuel conversion efficiency of 6%. Lastly, a hybrid tandem cell was also constructed using a polymer and a colloidal quantum dot subcell. Different hybrid tandem device architectures were proposed and show a promising PCE of 6.7%.

I detta examensarbete har syftet varit att undersöka hur man kan minska behovet av att behöva köpa energi till en fastighet med tillhörande byggnader. Fokus har legat på att producera nog med energi för att täcka fastighetsägarnas konsumtion av el. Projektet har även berört energioptimeringsåtgärder av enklare slag. Efter detta gjordes en fysisk genomgång av byggnaderna där mätning också genomfördes dels som underlag för en energibalans, dels som underlag när det undersöktes vilka energisparåtgärder som var ekonomiskt genomförbara, såsom tillläggsisolering av vinden. Sedan samlades det in offerter och annan viktig information, såsom energiproduktion och priser, för att sedan analyseras. Alla delar jämfördes och ställdes mot varandra för att komma fram till det som passade fastighetsägarna bäst. Lagring och vindkraft hade en för lång återbetalningstid gentemot vad ägarna hade efterfrågat då de ville att det skulle vara återbetalat innan produkternas livslängd var slut. Resultatet av vindkraften visade att vindhastigheterna inte kunde fastställas helt eftersom den vindmätning som gjorts har skett 25 km därifrån, vilket leder till en osäkerhet i hur mycket el som kan produceras. Det mest lönsamma var den största av de fyra solcellsparker som jämfördes. Den och det lilla vindkraftverket tillsammans producerar tillräckligt mycket el för att täcka deras behov. Däremot rekommenderades varken vindkraftverket eller batterilagring på grund av återbetalningstiden. Ägarna kan alltså producera den mesta elen med hjälp av solceller, dock inte allt enligt de beräkningar som gjorts. Förutom Vattenfalls solceller rekommenderades att tilläggsisolera vinden samt en laddbox från Vattenfall. Eftersom teorin i examensarbetet skulle baseras på granskade källor och inte på vinstdrivande källor användes studentlitteratur, publicerade rapporter och rapporter från myndigheter. / The purpose of this thesis has been to examine how to reduce the need to buy energy for a property with associated buildings. The focus has been on producing enough energy to cover the property owners' consumption of electricity. The project has also involved simpler energy optimization measures. After this, a physical review of the buildings was carried out, where measurement was also carried out partly as a basis for an energy balance and partly as a basis when examining which energy saving measures were economically feasible, such as additional insulation of the wind. Then quotes and other important information, such as energy production and prices, were collected and then analyzed. All parts were compared to each other to arrive at what best suited the property owners. Storage and wind power had too long a payback period against what the owners had asked for when they wanted it to be repaid before the end of product life. The result of the wind power showed that the wind speeds could not be fully determined since the wind measurement made was 25 km away, which leads to an uncertainty in how much electricity can be produced. The most profitable was the largest of the four solar cell parks compared. It and the small wind turbine together produce enough electricity to meet their needs. However, neither the wind turbine nor the battery storage was recommended because of the payback time. The owners can thus produce most of the electricity using solar cells, but not all according to the calculations made. In addition to Vattenfall's solar cells, it was recommended to insulate the wind and install a charging box from Vattenfall. Since the theory in the degree project should be based on audited sources and not on profit-making sources, student literature, published reports and reports from authorities were used.

Orientador: Maria Glória Caño de Andrade / Resumo: Este trabalho é baseado no estudo do comportamento de um diodo PIN de multicamadas utilizado como célula solar. Esse estudo é desenvolvido por meio de simulações em ambiente virtual, validada a partir de dados experimentais, e tem como foco principal o comportamento da geração de corrente pelo dispositivo, tanto na interação entre o dispositivo e uma determinada faixa do espectro luminoso, como na influência que as alterações nas dimensões dessa célula solar podem trazer na tensão gerada. O diodo PIN proposto encontra-se em uma lâmina SOI (Silicon On Insulator) com uma potencial aplicação destinada para a alimentação de circuitos que necessitam de ultrabaixa potência (ULP – Ultra Low Power), tais como sensores de campo para monitoramento e circuitos subcutâneos para monitoramento médico. É construído por uma camada dupla com diferentes semicondutores (silício e germânio) e, através de alterações em sua estrutura (mudança dos materiais e das dimensões), será verificado o comportamento dos principais parâmetros de uma célula solar, tais como fator de forma (FF), corrente fotogerada, tensão de circuito aberto, corrente de curto-circuito, tensão e corrente de trabalho e potência gerada pelo dispositivo. Adicionalmente, é também analisado o comportamento de penetração e absorção do espectro luminoso na célula solar e a existência de alterações nos parâmetros medidos quando há alteração na posição das camadas de semicondutores, com a finalidade de demonstrar que o incremento de uma... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work is based on the study of multilayer PIN diode used as a solar cell. This study was developed through simulations in a virtual environment with the main focus of the generation current by the device so much in the interaction between the device and a range of the light spectrum as well as in the influence the changes in the dimensions of the solar cell may bring in the voltage generated. It is composed of a double layer with different semiconductors (silicon and germanium), and though changes in its structure (materials and dimensions change), it will be verified the behavior of main parameters of a solar cell, such as Fill Factor (FF), photogenerated current, open-circuit voltage, short circuit current, work voltage and work current and the generated power will by the device. Additionally, it was also verified the behavior of the penetration and absorption of the light spectrum in the solar cell, and the existence of changes in the measured parameters when there is a change of position in the semiconductor layers, to demonstrate that the increase of a germanium layer may bring to the device concerning entirely silicon device. The results obtained indicate that there was an increase in the photogeneration when the germanium layer is positioned above the silicon layer. This way, this work demonstrates that small changes in the construction and the thickness of the lateral PIN diode used as a solar cell provide an increase in efficiency of more than 136% when comparing... (Complete abstract click electronic access below) / Mestre

<p>Thin film photovoltaic materials have garnered much interest recently due to their processability in addition to good properties for conversion of solar photons to usable energy. Amine-thiol chemistry has shown the ability to produce solution processed materials such as Cu₂ZnSn(S,Se)₄ (CZTSSe), a thin film absorber composed of earth abundant metals. Using similar solution processing methods as those used to produce CZTS, we wish to synthesize a phase pure solution processed material from molecular precursors of metals and metal chalcogenides into an Ag₂ZnSnSe₄ absorber which lacks the electronic defects that plague CZTSSe. Additionally, we will utilize the reactive dissolution of metal in amine-thiol solution chemistry for a more detailed understanding of how metal-sulfur complexes form and then decompose into films, to gain insight about the conditions that produce stable solutions and high quality films for a better ability to optimize processing conditions. </p><p><br></p><p>We find we are able to individually dissolve zinc metal, tin metal, and silver sulfide precursors to produce solutions of metal thiolate complexes. Based on results from electrospray ionization mass spectrometry (ESI-MS), proton nuclear magnetic resonance (¹H-NMR), and extended X-ray absorption fine structure (EXAFS)/ X-ray absorption near edge spectra (XANES) we propose that these structures contain thiolate molecules coordinated with Ag, Zn, and Sn in the +1, +2, and +2 oxidation states respectively. However, mixing these produces an AZTS solution which is only stable for 3 hours, due to a redox reaction between Ag⁺ and Sn²⁺ which forms Sn⁴⁺ and insoluble Ag metal. To solve this, we synthesize SnS₂ and show this produces a different Sn-thiolate complex with fully oxidized Sn⁴⁺. This is then used to produce the first stable AZTS solution, an essential step to fabricating reproducible films. We use this AZTS solution to fabricate films containing AZTS, and selenize these films in a tube furnace to produce films which contain AZTSe as well as secondary phases. We then use rapid thermal processing furnace to remove some of these secondary phases, and discuss ways to further improve our material quality.<br></p><p></p>

Thin film solar cells, such as Cu(In,Ga)Se2, have a large potential for cost reductions, due to their reduced material consumption. However, the lack in commercial success of thin film solar cells can be explained by lower efficiency compared to wafer-based solar cells. In this work, we have investigated the aluminum oxide as a passivation layer to reduce recombination losses in Cu(In,Ga)Se2 solar cells to increase their efficiency. Aluminum oxides have been deposited using spatial atomic layer deposition. Blistering caused by post-deposition annealing of thick enough alumina layer was suggested to make randomly arranged point contacts to provide an electrical conduction path through the device. Techniques such as current-voltage measurement, photoluminescence and external quantum efficiency were performed to measure the effectiveness of aluminum oxide as a passivation layer. Very high photoluminescence intensity was obtained for alumina layer between Cu(In,Ga)Se2/CdS hetero-junction after a heat treatment, which shows a reduction of defects at the absorber/buffer layers of the device.

Denna rapport bygger på den kommande solcellsfasaden på kvarteret Frodeparken i centrala Uppsala. Projektet genomförs genom ett partneringavtal mellan Skanska Sverige AB och Uppsalahem. Syftet med detta examensarbete var att skapa en underhållsplan samt en investeringskalkyl för projektet. En teknisk bakgrund för solcellsanläggningar har sammanställts för att förstå hur systemet fungerar. Underhållsplanen grundas på fakta från solcellsleverantören och uppgifter från referensobjekt. Det har visat sig att solcellsanläggningar kräver väldigt lite underhåll. För att få en bred syn på investeringen har ett antal simuleringar på investeringskalkylen genomförts. Vilka har visat att det är svårt att få en investering på en solcellsanläggning lönsam. Då tekniken är under utveckling är det inte omöjligt att den blir det i framtiden. / This report is about the solar facade on the future building kvarteret Frodeparken in the central part of Uppsala. The project implemented through a partnering agreement between Skanska Sverige AB and Uppsalahem. The purpose with this task was to create a maintenance plan and an investment calculation of the project. A summary of the solar cell technology has been done to understand how the system is going to work. The maintenance plan is based on facts from the solar cell supplier and data from the reference objects. It has been shown that the solar cells need very little maintenance. To get a wider view of the investment have a number of simulations on investment calculations been done. Who has shown that it is difficult to get an investment of solar cells profitable. The technology is constantly evolving which may give it a chance to bright in the future.

No description available.

The endeavor to have more efficient solar cells and as environmentally beneficial as possible are the driving forces for this work. The way to reach this is by research to better the understanding of the mechanisms and parameters that govern the performance of solar cells. New materials are essential to develop because the current ones lack stability and are water, temperature and UV-radiation sensitive. In this work the lead (Pb2+), which is poisonous and hazardous is intended to be replaced in the organic metal halide (OMH) perovskite structure. This is tested with gold or silver combined with bismuth and silver by itself. Also trimethylsulfonium gold or silver iodides are investigated. The methylammonium cation is also substituted to cesium. The perovskite material both absorbs light and transports charges in the solar cells. Materials based on AuI/AgI, BiI3 and CH3NH3I and AuI/AgI and [Me3S]I and AgI, BiI3 and CsI were synthesized and analyzed by XRD on thin film and mesoporous substrate and Raman spectroscopy to determine material structure and bonding. J-V measurements were performed to see the function in solar cells. After this conductivity and absorption parameters were determined by an electrical conductivity test and UV-vis absorption spectroscopy. XRD measurements indicate that the perovskite structure could have been obtained because the materials match with the XRD spectra of [20] foremost T3, T5 and T6, Cs1 and Cs2. In T7 some new structure is formed. The bismuth could be partially substituted by silver as the metal cation. The samples are quite amorphous, but still containing crystalline peaks, the product material could be a mixture of a crystalline and an amorphous phase. The crystalline phase could have the desired perovskite structure. To have mesoporous TiO2 as substrate seem to enhance a more crystalline structured material. All the materials seem to have formed some new structures because the pure reactants does not seem to be present, exceptions could be P1 and T1 that contained AuI. The change of cation from methylamine to cesium though results in a shift of the peak positions because of the change of cation size as in [20], but the structure is most likely the same. Raman spectroscopy indicate that there is a change in structure, some new bond being present, when increasing the methylamine ratio for the presumed methylammonium silver bismuth iodide perovskites. This concerns materials T5, T6, T7 with increasing ratio of methylamine. This new bond is most pronounced in T7 where the methylamine content is the highest. Both Silver and bismuth iodide bonds seem to be present and cannot be coupled to be the pure reactants recrystallizing and some new bonds of these are present in all materials to some extent. The organic bond vibration has low intensity and might indicate that there is not so much organic cation present in the product and thus the probability of having the desired product anion decreases. The solar cells made with Spiro-OMeTAD were 700-4000 times more efficient than those made with Sulphur polymer HTM. Solar cells made with Spiro-OMeTAD as HTM gives slightly higher efficiency when increasing the methylammonium cation ratio. For cesium as cation the combined metal cation constellation with bismuth and silver gives a little higher efficiency than bismuth alone. Methylammonium as cation gives a higher efficiency than cesium. Solar cells made with Sulphur polymer HTM show approximately 3-30 times higher efficiency with methylammonium as cation compared to cesium as cation. HTM material seem to affect the perovskite material making some of the cells completely transparent and some of them paler, water in the solvent chlorobenzene can be a possible explanation. The transparency can be the reason for the low efficiency obtained for the solar cells. Also the measurement methodology of these solar cells can also have been false, measuring the contacts, and the etching procedure could be another source of this. The solar cells had quite low efficiencies compared to [20], although same presumed material and procedure has been used and thus there might be something wrong in the accuracy of the manufacturing. The cells should probably been made several times and possible sources of error should be analyzed and corrected for. The materials were all relatively conductive. P1 gave the highest conductivity, almost three times higher than for methylammonium lead iodide that has a conductivity of 1,1x10-4 s/cm [3]. Increasing the methylammonium ratio gave an increase of the conductivity both with bismuth and silver as metal cations and silver alone. The increase of the methylammonium ratio might result in a new structure formed which has lattice planes that are more conductive. A change of gold to silver for the trimethylsulfonium iodide materials gave a large decrease in conductivity. The materials have different absorption curves meaning that they have different bandgaps and this indicates differences in structure. The bandgaps of all materials are indirect contrary to what is proven to be the case for perovskites that are believed to have direct bandgaps in general. To have indirect bandgaps requires a shift in momentum in the electronic transitions and is not as beneficial as having direct bandgaps. Compared to methylammonium lead iodide that has a direct bandgap of 1,6 eV, the bandgaps are at least 0,5 eV higher and range between 2,2-2,36 eV. P1 had a low bandgap of 1,6 eV meaning it absorbs a wide range of wavelengths. The conductivity does not seem to be the obstacle and the cells that are not transparent absorb light. It is highly possible that the low solar cell performance, at least to a certain extent, has to do with the production process. The low scan rate could also affect the low efficiencies and HTM Spiro-OMeTAD should be used. Currently the efficiency of the perovskite materials with silver/bismuth, gold/bismuth and silver are too low, and not able to substitute lead in the perovskite structure solar cells. Neither trimethylsulfonium gold or silver iodide cells nor cesium perovskites have enough efficiency at present. The conductivities for the materials are promising and the materials that are not completely transparent absorb light. / Strävan att utveckla effektivare solceller och så miljövänliga som möjligt är drivkrafterna för det här arbetet. För att uppnå detta krävs forskning för att förbättra förståelsen för vilka mekanismer och parametrar som styr hur väl solcellerna fungerar. Det är nödvändigt att ta fram nya material, då de nuvarande brister i stabilitet, de är framförallt känsliga för vatten, temperatur och UV-strålning. I det här arbetet är syftet att byta ut bly (Pb2+), som är giftig och kopplad till hälsorisker, i den organiska metall halid (OMH) perovskit strukturen. Detta görs med guld eller silver i kombination med vismut och silver självt. Även trimetylsulfonium- guld eller silver undersöks. Metylammonium katjonen substitueras också mot cesium. Perovskit material absorberar både ljus och transporterar laddningar i solceller. Material baserade på AuI/AgI, BiI3 och CH3NH3I and AuI/AgI och [Me3S]I and AgI, BiI3 and CsI syntetiserades. Dessa analyserades, med XRD på dels ett substrat av tunn film och dels ett mesoporöst och Raman spektroskopi, för att bestämma strukturen på materialet och bindningar. J-V mätningar utfördes för att se hur materialen fungerade som solceller. Efter detta utfördes mätningar av konduktiviteten och absorptions parametrar bestämdes genom ett elektriskt konduktivitetstest respektive UV-vis absorptions spektroskopi. XRD mätningarna indikerar att perovskit strukturen kan ha erhållits eftersom spektrumen överensstämmer med de i [20], framförallt för T3, T5 och T6, Cs1 och Cs2. I T7 bildas någon ny struktur. Vismut skulle kunna vara delvis utbytt mot silver som metalkatjon. Proven är relativt amorfa, men uppvisar kristallina toppar och produkten skulle kunna vara en blandning av en kristallin och amorf fas, där den kristallina fasen skulle kunna ha den eftersträvade perovskit strukturen. Mesoprös TiO2 som substrat verkar öka graden av kristallinitet hos materialen. Samtliga material verkar ha bildat någon ny struktur eftersom reaktanterna i sin rena form inte verkar finnas. Undantag skulle kunna vara P1 och T1, vilka innehåller AuI. Bytet av katjon från metylammonium mot cesium resulterar i ett skifte av topparna troligen beroende av skillnaden i storlek mellan katjonerna, liksom påvisas i [20], men strukturen är förmodligen densamma. Raman spektroskopin indikerar en förändring i strukturen, någon ny bindning finns, hos materialen när metylammonium andelen ökas för de förmodade metylammonium silver vismut jodid perovskiterna. Detta gäller materialen T5, T6, T7, där andelen metylammonium ökar. Den nya bindningen är mest uttalade i T7, där metylammonium andelen är den högsta. Både silver och vismut jodid bindningar verkar finnas och kan inte kopplas till att de rena reaktanterna har rekristalliserats och nya bindningar av dessa finns i alla material till en viss grad. Den organiska bindningens vibration har låg intensitet och kan tyda på att det inte finns så mycket organisk katjon i produkten och således minskar sannolikheten att ha den eftersträvade anjon produkten. Solcellerna gjorda med Spiro-OMeTAD var 700-4000 gånger mer effektiva än dom gjorda med Svavel polymer HTM. För solcellerna gjorda med Spiro-OMeTAD som HTM ger en ökning av metylammonium katjon andelen en ökad effektivitet. För cesium som katjon med den kombinerade metalkatjon konstellationen med vismut och silver, blir effektiviteten högre än om vismut är metalkatjon självt. Metylammonium som katjon ger en högre effektivitet än cesium. Solceller gjorda med Svavel polymer HTM visar ungefär 3-30 gånger högre effektivitet med metylammonium som katjon jämfört med cesium som katjon. HTM materialet verkar påverka perovskit materialet och göra några av cellerna helt transparenta och de andra blekare. Klor benzen användes som lösningsmedel och denna kan ha innehållit vatten och kan vara orsaken till färgskiftningen. Detta kan vara orsaken till den låga verkningsgraden som erhölls för solcellerna. En annan möjlig förklaring skulle kunna vara metoden för mätningarna. Denna kan ha varit felaktig, då kontakten troligen har varit det som har mätts och etsningsprocessen skulle kunna vara en orsak till detta. Solcellerna uppvisar ganska låg effektivitet i jämförelse med [20], trots att samma material och procedur har använts och således kan det vara något fel i precisionen av framställningen. Cellerna skulle förmodligen gjorts om ett antal gånger och möjliga felkällor borde utretts och åtgärdats. Materialen var överlag relativt konduktiva. P1 gav den högsta konduktiviteten, nära tre gånger högre än metylammonium bly jodid, som har en konduktivitet på 1,1x10-4 s/cm [3]. En ökning av andelen metylammonium gav en ökning av konduktiviteten både med vismut och silver som metalkatjon och silver självt. Ökningen av andelen metylammonium skulle kunna resultera i ett en ny struktur uppkommer som har plan som är mer konduktiva. Utbytet av guld mot silver för trimetylsulfonium jodid materialen gav en markant sänkning av konduktiviteten. Materialen har olika absorptionskurvor vilket innebär att de har olika bandgap och detta indikerar olikheter i strukturen. Bandgapen för alla material är indirekta, trots att bandgapen för perovskiter i regel är direkta. Att ha indirekta bandgap kräver ett skifte i momentum i de elektroniska energiöverföringarna och är inte så fördelaktigt som att ha direkta bandgap. I jämförelse med metylammonium bly jodid, som har ett direkt bandgap på 1,6eV, är bandgapen minst 0,5 eV högre och varierar mellan 2,2-2,36 eV. P1 hade ett lågt värde på bandgapet, 1,6 eV, vilket innebär absorption av ett brett spektrum av våglängder. Konduktiviteten verkar inte vara den faktor som är orsaken till den låga effektiviteten hos solcellerna och de celler som inte är transparenta absorberar ljus. Det är högst troligt att den låga effektiviteten har sin förklaring, åtminstone delvis, i produktionsprocessen för solcellerna. Den relativt låga skanningshastigheten kan också vara en orsak för den låga effektiviteten och HTM Spiro-OMeTAD bör användas. I dagsläget är effektiviteten för perovskitmaterialen med silver/vismut, guld/vismut och silver för låg och har inte möjlighet substituera bly i perovskit solceller. Inte heller trimetylsulfonium guld eller silver jodid cellerna och inte heller cesium perovskiternas effektivitet räcker till i dagsläget. Konduktiviteten för materialen är lovande och materialen som inte är transparenta absorberar ljus.

<div>The Internet-of-Things (IoT) devices have experienced an explosive growth during the last decades. The number of IoT devices is predicted to reach 36.4 billion by 2025, resulting in an urgent demand for high-density and high-capacity network connectivity. Recently, self-powered optical wireless devices have attracted more attention from both academia and industry. Although radio frequency (RF) technologies are readily available for various wireless applications, the RF</div><div>communication bands are becoming saturated due to the scarcity of the RF spectrum. Optical wireless communication (OWC) provides an attractive solution to overcome the shortage of RF bands. OWC is also attractive for low-power or even self-powered applications since optical energy is the most abundant in both indoor and outdoor scenarios.</div><div><br></div><div>This dissertation explores a new optical communication technique called optical frequency identification (OFID). This technique employs solar cells as an optical antenna, capable of harvesting energy and transmitting/receiving optical information. Transmission of information with a solar cell is achieved by modulating the cell's luminescent emissions. Two OFID system prototypes were designed,</div><div>fabricated, evaluated, and discussed.</div><div><br></div><div>A series of experiments have been carried out to exploit the feasibility of using a solar cell's luminescence emissions for optical communication and evaluate proposed two OFID system prototypes. This dissertation validated that luminescent emissions from a GaAs solar cell can be modulated for optical communications. Then, two photoluminescence (PL) modulators were proposed and compared in terms of their energy harvesting and communication performances. The first OFID system prototype, based on a dual-aperture reader and a microcontroller-based tag was validated and experimented for a remote temperature sensing application. The second prototype, based on a single-aperture OFID reader and an FPGA-based OFID module, was analyzed with an emphasis on the communication date rate, communication range, tag's cold-startup period and power consumption.</div>