High Performance Polymer/Perovskite Solar Cells For Indoor Applications

Internet of Things(IoTs)devices cannot operate without a stable power supply,and photovoltaic devices for indoor applications can power a variety of small electronic devices.However,how to choose the appropriate material system and device structure to achieve high power conversion efficiency(PCE)of devices in indoor lighting environment has always been a key scientific and technological problem to be solved.In this paper.from the point of view of selecting the materials and structures of devices for indoor applications reasonably and optimizing the fabrication process of devices,two new material structures were proposed and the corresponding high performance devices were fabricated.The main contents of this paper are as follows:a.Wide-bandgap active layer materials,including the benzotriazole-based polymer donor J52-F,chlorinated polymer donor PM7 and acceptor BTA3 with A2-A1-D-A1-A2 structure,were used to construct ternary polymer solar cells for indoor applications.The PCE of the device is greatly improved by introducing the third component PM7 into the binary blend based on J52-F:BTA3.The PCE of the device is 20.04%and the open circuit voltage(VOC)is 1.00 V under the test conditions of the light-emitting diode(LED)lighting source with the color temperature of 3000 K and the illumination of 300 lx.The excellent performance of ternary polymer solar cells is inseparable from matched spectral,enhanced light absorption and reduced energy loss(Eloss),improved charge transfer capacity and inhibition of carrier recombination also play an indelible role.This work presents a new material structure system that can meet the requirements of indoor lighting applications.Furthermore,this work shows that the design of ternary polymer solar cell systems is indeed a feasible solution to further improve the performance of polymer solar cell devices for indoor applications.b.Two kinds of inorganic perovskite solar cells based on CsPbI2Br and CsPbI2Br+Pb(Ac)2 thin films were fabricated for indoor applications.After adding a certain amount of Pb(Ac)2 to CsPbI2Br thin film,the device’s filling factor(FF)and PCE value do not decrease,and the device’s Voc value is greatly increased,which makes it more suitable for indoor applications.The optimized CsPbI2Br+Pb(Ac)2 thin film device has a Voc of 1.31 V and a PCE of 12.76%at AM 1.5 G.Under the test conditions of LED lighting source with color temperature of 3000 K and illumination of 1000 lx,the device’s Voc is 1.13 V and PCE is 28.54%,which shows its excellent low-light performance.In addition,adding a certain amount of Pb(Ac)2 can increase the water contact angle of perovskite film and improve the hydrophobicity of the film,which makes it more suitable for use in high humidity environment.The CsPbI2Br+Pb(Ac)2 thin film device retains 98%of its initial PCE after 14 days in air(25℃ and 30%humidity).This work not only fabricated the all-inorganic perovskite solar cells with excellent PCE and stability under indoor lighting conditions,but also provided a new idea for the fabrication of photovoltaic devices for indoor applications.