Metal oxide nanoparticles as carrier transport layer in perovskite solar cells application

Abstract

Solar energy is clean and sufficient energy to meet the requirement of sustainable development. Solar cells are the devices that directly convert solar energy to electricity have been under extensive investigation. Perovskite solar cells (PSCs) consist of perovskite crystals that serve as light absorbers sandwiched between a semiconductor pn junction. SnO2 nanoparticles and NiOx nanoparticles are two popular carrier transport layers in conventional (n-i-p) PSCs and inverted (p-i-n) PSCs, respectively. These metal oxide nanoparticle carrier transport layers in PSCs application are the major research topics in this thesis. SnO2 nanoparticles with the advantage of low processing temperature, high conductivity, and high stability have been widely applied in PSCs as electron transport layer (ETL). hydrothermal parameters have an impact on SnO¬2-based PSCs. Moreover, SnO2 nanoparticles consist homojunction bilayer with underneath 3 nm atomic layer deposition (ALD) deposited SnO¬2, the bilayer SnO¬-2-based PSCs have enhancement on open circuit voltage (VOC) and fill factor (FF). PSCs’ hysteresis was also reduced in ALD-SnO2/SnO2 nanoparticles ETL. Inverted PSCs exhibited low hysteresis. and among many of organic and inorganic hole transport layers (HTLs), NiOx nanoparticles are superior in low post-annealing temperature and high stability. in thesis study, to achieve PSCs >20 % efficiency, self-assembly monolayer of (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz) was adopted. However, NiOx/2PACz HTL incurred fast degradation of PSCs under illumination. One possible explanation is that 2PACz introduced a large dipole causing undesirable band bending. This issue was solved by introducing ethanolamine between NiOx and 2PACz. The band banding in perovskite in flattened by amine-2PACz dual modification. These dual passivation archiving NiOx-based PSCs with average efficiency of 20 % and T95 stability over 300 hours with marking output current under illumination with load at maximum power point (MPP). NiOx nanoparticles were applied in flexible PSCs. Flexible substrate lack resistance to moisture and oxygen, resulting in poor stability. Thus, three substrates modifications were studied, which are ZnO nanorod with 1H,1H,2H,2H-Perfluorooctyltriethoxysilane (PFOTES) coating; IC1-200 spin on glass materials; ALD deposited Al2O3. All the substrate modifications improved the stability of flexible PSCs. And reduced water vapor transmission rate (WVTR) measured via Ca test.