Growth manipulation in electrodeposition of compact and mesoporous electron transport layers for enhanced efficiency and stability in carbon-based perovskite solar cells

Abstract

Electrodeposition is a low-cost and mature industrial technique for large-scale perovskite solar cells (PSCs) manufacturing. The present work provides new insights into developing compact and mesoporous electron transport layers for PSCs via the electrodeposition technique in one pot. By the precise control of current density and deposition duration during the process, both the compact blocking layer and mesoporous layer can be stepwise developed, with optimized structural, morphological and optoelectrical characteristics for solar cells application. Herein, TiO₂ electrodeposited thin films are developed, with low defect density, high crystallinity and beneficial morphology for their subsequent application as substrates for perovskite heterogeneous nucleation. In this direction, the scalable electrodeposited PSCs developed under the optimized manufacturing protocol demonstrated power conversion efficiency (PCE) up to 10.83 %, significantly surpassing the 6.85 % record of the spin-coated devices. The increased light harvesting efficiency, enhanced absorbed-photon-to-electron quantum efficiency and low charge recombination losses in the electrodeposited solar cells were identified as determent factors for this PCE enhancement. The stability of the unencapsulated devices under ISOS-D-1 protocol conditions was also found increased, with their T₇₀ exceeding 1000 h. This study highlights a scalable approach for the development of highly efficient and stable perovskite photovoltaics.