Metal‐Nanowire‐Electrode‐Based Perovskite Solar Cells: Challenging Issues and New Opportunities

Abstract

in PSCs has been accomplished within a relatively short period of time, owing to OMHP's merits for low-cost, large-area, flexible photovoltaic applications; these merits include (i) the precursor chemicals, including organic ammonium halides and lead (tin) halides, for synthesizing the OMHP materials are cost-effective, and the OMHP layers can be readily prepared by simple wet-chemical approaches such as a spin coating or a slot-die coating process; (ii) the processing temperatures are relatively low, below 150 °C, for the formation of well-crystalized OMHP layers, in contrast to other thin-film-based solar cells; (iii) both the high absorption coefficients [6] and high carrier mobilities [7] suggest promising possibilities for highperformance photoactive materials. The PCE certified by National Renewable Energy Laboratory (NREL) reached 22.1% in 2016, [8] which is either comparable to or outperforms the PCEs of other next-generation thin-film solar cells, including CIGS(Se) (22.3%), CZTS/Se (12.6%), CdTe (22.1%), and organic photovoltaics (OPVs, 11.5%).Apart from the race to achieve higher PCE, other important research has been directed toward the development of lead-free OMHP layers, [9] large-area device fabrication, [10,11] a methodology of achieving long-term stability against moisture and irradiation, [12,13] and a way of recycling constituent cell materials. [14] Another fascinating research topic concerns the electrodes for PSCs. To date, vacuum-deposited transparent conductive oxides (TCOs), such as indium tin oxide (ITO) and fluorinated tin oxide (FTO), have been used widely as a large-area window electrode through which light passes. However, TCOs have received criticism in terms of their fabrication cost, brittleness, and the scarcity of raw materials (especially, the indium in ITO). [15] Opaque noble metal electrodes (Au, Ag), which are usually used as a back contact, are also fabricated with a costly vacuum-assisted deposition process. From the viewpoint of cost-effectiveness, both transparent and opaque conventional electrodes apparently represent predominant impediments to the high-throughput fabrication of PSCs, giving rise to a significant demand to replace these conventional electrodes with alternatives.To date, a variety of alternative electrodes have been reported in the literature.

All‐Solution‐Processed Silver Nanowire Window Electrode‐Based Flexible Perovskite Solar Cells Enabled with Amorphous Metal Oxide Protection

“…[24] Previously, our group demonstrated the feasibility of using AgNWs as all-solution-processed TCEs in which the AgNWs are sandwiched between combustion sol-gel derived conductive oxides of ITO and ZnO, resulting in a PCE of 8.44% on a rigid substrate. When these AgNWs are utilized as window electrode in PVSCs, high PCEs of 13.93% (on a rigid substrate) and 11.23% (on a flexible substrate) could be achieved, which are comparable to the PCEs of traditional transparent electrode based PVSCs (15.72% on FTO glass and 13.56% on an ITO/ polymer electrode). Accordingly, in this study, we demonstrate that solution-processed indium-free amorphous Al-doped zinc oxide (a-AZO) can serve as a protective layer for AgNW.…”

“…After optimizing the thickness of the a-AZO layer on AgNWs, indium-free vacuum-free all-solution-processed transparent electrodes exhibit optoelectrical properties comparable to those of conventional fluorine doped tin oxide (FTO) or ITO electrodes. When these AgNWs are utilized as window electrode in PVSCs, high PCEs of 13.93% (on a rigid substrate) and 11.23% (on a flexible substrate) could be achieved, which are comparable to the PCEs of traditional transparent electrode based PVSCs (15.72% on FTO glass and 13.56% on an ITO/ polymer electrode). Notably, the PVSCs fabricated with flexible a-AZO/AgNW/AZO-based electrodes can endure 400 bending iterations with a bending radius of 12.5 mm, while maintaining 94% of their initial PCE.…”

Perovskite/Silicon Tandem Solar Cells: Marriage of Convenience or True Love Story? – An Overview

“…Silver nanowire mesh electrodes were demonstrated by several groups, usually deposited by spray coating and mechanical transfer . Questions about stability were however rapidly raised, due to the formation of silver halide complexes through reaction with ions from the perovskite layer .…”

Extremely lightweight and ultra-flexible infrared light-converting quantum dot solar cells with high power-per-weight output using a solution-processed bending durable silver nanowire-based electrode

“…Therefore, the Ag NWs are believed to be one of the most promising electrode materials for the flexible photovoltaic or optoelectronic devices. [39][40][41][42] The performance of the metal NW-based electrode generally increases with the decrease in the diameter of the NW, while the increase in the NW length/diameter aspect ratio will reduce light scattering and decrease the resistance in the film. [43][44][45][46][47][48][49] Therefore, in this study, Ag NWs with an average aspect ratio of 5000 (average diameter of B30 nm and length of 100-200 um, Fig.…”