A bismuth silver pnictohalide alternative to perovskite in fully-printable triple-mesoscopic solar cells

Recent Ag3BiI6 solar cells have demonstrated promising efficiency, however, most have focused on mesoporous n-i-p configuration, using expensive hole transport materials (e.g., P3HT, PTAA and spiro-OMeTAD) and a Au counter electrode. To lower the cost and potentially enable larger scale Ag3BiI6 solar cells, herein, this study provides the first feasibility examination of Ag3BiI6 in fully-printable triple-mesoscopic (TiO2/ZrO2/carbon) solar cells (TM-SCs) and explores the effect of pre-treatment with small molecules and post-treatment (CuSCN) on the overall Ag3BiI6 TM-SC performance. An Ag3BiI6 solar cell with a power conversion efficiency (PCE) of 0.38% (J(sc) = 1.97 mA cm(-2); V-oc = 0.49 V; fill factor = 0.39) is demonstrated under 1 sun irradiation with two-month dark-storage stability in the ambient atmosphere. An improved V-oc from 0.43 V to 0.48 V was observed with biPY pre-treatment; a champion PCE of 0.74% (J(sc) = 2.78 mA cm(-2); V-oc = 0.56 V; fill factor = 0.48) was achieved with CuSCN post-treatment. The results reported here represent a step toward developing all inorganic Bi-based absorbers in printable TM-SCs, suggesting that further improvements should be possible with porous surface engineering and efficient charge extraction.

Automated summary

Recent studies have focused on improving the efficiency of Ag3BiI6 solar cells, but most have overlooked cost-effectiveness and scalability. This study explores the feasibility of Ag3BiI6 in fully-printable triple-mesoscopic solar cells and investigates the effect of pre-treatment and post-treatment on their performance. The results show a potential for developing all inorganic Bi-based absorbers in printable solar cells.