Revolutionizing environment friendly FASnI3 perovskite solar cells with pioneering selenium doped metal chalcogenide charge transport layer unlocking 32% efficiency
Akash Anand Verma, D. K. Dwivedi
Abstract
Due to extended thermal carrier lifespan, small bandgap, and biocompatibility, tin (Sn)-based perovskite solar cells (PSCs) have garnered attention. Sn-based PSCs (nip-type), however, have performed poorly, mostly because of the careless application of metal oxide electron transport layers (ETLs), which were first created for lead-based PSCs of the nip type. The metal oxides deeper energy levels and oxygen vacancies are too responsible for this underperformance. In order to overcome these problems, we demonstrate a metal chalcogenide ETL, namely Sn(S 0.92 Se 0.08 ) 2 , which prevents the oxidation of Sn 2+ and avoids the desorption of oxygen molecules. The variation of several charge transport layers is thoroughly analyzed in this work, indicating that SnS 2 , TiO 2 , and metal-doped Sn(S 0.92 Se 0.08 ) 2 are viable options to improve the efficiency of the FASnI 3 (Energy gap (E g ) ≈ 1.41electron volt (eV) PSC. With Sn(S 0.92 Se 0.08 ) 2 as ETL and PTAA as Hole transport layer (HTL), the PSC’s performance is maximized and the optimal performance device structure is attained. For our investigation, the optimal device structure is (Au/PTAA/FASnI 3 /Sn(S 0.92 Se 0.08 ) 2 /FTO). We obtain an outstanding optimized value of Power conversion efficiency (PCE) 32.22%, Open circuit voltage (V OC ) 1.2762 V, Fill factor (FF) 81.87%, and Short-circuit current density (J SC ) 30.836 mA.cm − 2 by carefully evaluating and optimizing a number of variables, such as thickness of active layer, ETL and HTL, Acceptor density (N A ), Defect density (N t ) vs. thickness variation, Interface defect (IDD) and temperature variation. These findings provide a viable pathway for enhancing the efficiency of Sn-based PSCs.