All‐Transparent Oxide Photovoltaics: AZO Embedded ZnO/NiO/AgNW Band Selective High‐Speed Electric Power Window

Abstract

generate energy from the invisible radiation of the sun, while protecting us from harmful UV radiation and pollution, by employing the essential elements of a net-zero emission energy system. [3,4] The EPW is driven by UV light while simultaneously transmitting the visible spectrum, and in this way offers onsite energy generation to power micro-scale devices, for example, the internet of things. [3][4][5][6] To be environmentally effective, the system should be made from sustainable materials such as metal-oxide and organic photovoltaics. [3,[7][8][9][10][11][12] Among metal-oxides, ZnO is nontoxic, earth-abundant, and offers a bandgap of 3.2 eV, easy doping, and exciting optoelectronic processes. Tetrahedral coordination in this material results in a non-central symmetric structure and piezoelectric and pyroelectric characteristics, [13][14][15][16][17][18][19][20][21] which can be exploited by energy harvesters, for examples nano-generators [22] and other energy harvesting systems. [23][24][25] The high visible light transmittance of ZnO also makes it a potential candidate for transparent photovoltaics. [26] There have been efforts to develop ZnO based transparent photovoltaics, however, current ZnO devices typically suffer from either low photocurrent or low photovoltage. [9,[27][28][29] Despite the novelty of this class of photovoltaics, the size of the device restricts its application in an electric power window, which requires a large area. Recently, we reported a ZnO based heterostructure with various optical features, for example, room temperature excitons, demonstrated in a broadband photovoltaic [30] and pyro-phototronics [31] photodetector, which has encouraged us to develop a ZnO/NiO based highly transparent versatile 1-in. square device with enhanced performance.Here, we report a back surface field embedded all-transparent ZnO/NiO oxide heterostructure for a multi-functional EPW. First, we studied the design aspects of the AZO/ZnO/NiO device using a 1D simulation. This design revealed the vital role of the AZO layer in improving the photovoltaic performance of the ZnO/NiO via the back surface field. Following this, we studied the electrical properties of wafer-scale AZO films grown by sputtering process, and discussed the tuning of mobility and donor density (N D ). We inserted a thin layer of AZO at the interface of the ZnO/FTO and studied its photovoltaic performance Electric power windows using an all-transparent oxide photoelectric device have the potential to shield and exploit ultraviolet radiation. Herein, an Al:ZnO embedded large area all-transparent ZnO/NiO electric power window is presented. A large-scale (1-in. square) device fabricated with the structure of FTO/AZO/ZnO/NiO/AgNW exhibits a visible light transmittance >70% and photovoltaic performance with an enhanced power conversion efficiency of 3.13% under UV illumination (λ = 365 nm). The spectral attributes of this heterostructure are analyzed using I-V plots, photoresponse, and photo-carrier lifetime (τ), which reveal the co-occurren...

UV‐Selective Optically Transparent Zn(O,S)‐Based Solar Cells

“…[ 6,7 ] To date, state‐of‐the art UV‐selective solar cells are mainly based on the use of ZnO as the absorber material. [ 8–13 ]…”

“…[6,7] To date, state-of-the art UV-selective solar cells are mainly based on the use of ZnO as the absorber material. [8][9][10][11][12][13] However, there are some important caveats that limit the use of ZnO for such solar cells. First, related to polarity and charge transport properties, being the fact of lack of bipolarity (i.e., p-type ZnO) which prevents the fabrication of homojunctions in conventional p-n configuration and also the synthesis of p-ZnO as absorber.…”

Large-Scale Transparent Photovoltaics for a Sustainable Energy Future: Review of Inorganic Transparent Photovoltaics

“…A literature review indicated that inorganic TPVs have attracted considerable research interest since 2013 because of the improvements in photovoltaic performance, facilitated by the incorporation of various mechanisms, to overcome the factors that limit device efficiency [15,[33][34][35][36][37][38][39][40][41][42][43]. Over the past few years, several research groups have reviewed the technologies underlying TPVs, semi-transparent thin-film TPVs, and organic TPVs [6,26,[44][45][46].…”

“…In the TPVs, the p-n heterojunction is typically prepared using the reactive sputtering technique, and consequently, this review article highlights the optoelectrical properties of the reactivesputtered wide-band-gap metal-oxide films. II compares the optical and electrical properties of these metal oxides along with their deposition parameters [37,39,[47][48][49][50][51][52][53][54][55][56][57][58][59]. Figure 3 presents an energy-level diagram of both the p-type and n-type metal oxides [33,[60][61][62][63][64][65][66].…”

Ultrathin Wide‐Bandgap a‐Si:H‐Based Solar Cells for Transparent Photovoltaic Applications

“…State-of-theart inorganic UV-selective solar cells are mainly based on the use of ZnO or Zn(O,S) as the absorber material, but even though presenting high average visible transparency (AVT) values, they still have to overcome an efficiency limited to around 0.5%. [15][16][17][18][19] However, recently, there have been demonstrations on implementing a-Si:H in UV-selective metal-oxide-based solar cells, showing the possibility to overcome this PCE limitation, but at the cost of losing some transparency. [20] The use of a-Si based technologies in this emerging field of PV has added benefits in terms of the use of materials that are stable and durable, that are not deemed as critical raw.…”