Band Matching Strategy for All-Inorganic Cs₂AgBiBr₆ Double Perovskite Solar Cells with High Photovoltage

Abstract

The lead-free double perovskite has been proven to be one of the promising alternatives to solve the stability and toxicity problems of lead-based organic−inorganic hybrid perovskite solar cells. Here, highquality Cs 2 AgBiBr 6 double perovskite films with large grains and smooth surface have been prepared through a sequential-vapor-deposition method, and a low-cost and eco-friendly Cu 2 O film with a suitable energy level and good electrical properties was prepared as an efficient hole transport layer by vacuum vapor deposition for the first time. The Cu 2 O-based devices achieve a champion power conversion efficiency increasing from 1.03 to 1.52% and an enhancement of photovoltage from 1.083 to 1.198 V compared with their organic counterparts. More importantly, the Cu 2 Obased devices have excellent stability; they maintained the initial 96% efficiency under environmental conditions after 33 days of unpackaged storage. These results also point out the direction for the further development of these new promising perovskite solar cells.

The high open-circuit voltage of perovskite solar cells: a review

“…However, a remarkable V OC enhancement was realized using inorganic Cu 2 O as the HTM. 330 Because of its good electrical properties and well-matched energy level with Cs 2 AgBiBr 6 , the V OC was promoted to a record-high value of 1.20 V from 1.08 V observed in the case of Spiro HTM. But the PCE (1.52%) in the case was not impressive due to the lower J SC than other reported values.…”

Cs2AgBiBr6 Double Perovskites as Lead‐Free Alternatives for Perovskite Solar Cells?

“…[14] Yet, the highest efficiencies have been achieved without antisolvent, using either a mesoporous or compact TiO 2 scaffold as ETL. [15] The highest PCEs for solar cells comprising pure Cs 2 AgBiBr 6 were obtained modifying both hole-transport material (HTM) and ETL in order to improve the energy-level alignment, [64] as well as the charge carrier extraction. [16] While the stoichiometric ratios of the elements were discussed to influence the solar cell performance, [15,26] theoretical predictions regarding its effect on the optoelectronic properties do not provide a consistent picture.…”

“…[ 14 ] Yet, the highest efficiencies have been achieved without antisolvent, using either a mesoporous or compact TiO 2 scaffold as ETL. [ 15 ] The highest PCEs for solar cells comprising pure Cs 2 AgBiBr 6 were obtained modifying both hole‐transport material (HTM) and ETL in order to improve the energy‐level alignment, [ 64 ] as well as the charge carrier extraction. [ 16 ]…”

High Open‐Circuit Voltage Cs2AgBiBr6 Carbon‐Based Perovskite Solar Cells via Green Processing of Ultrasonic Spray‐Coated Carbon Electrodes from Waste Tire Sources

“…[35][36][37] Although the indirect bandgap of Cs 2 AgBiBr 6 is reported as 2-2.2 eV, [28][29][30] PSCs based on this material have been characterized by open-circuit voltages (V OC ) that, to the best of our knowledge, are close to or, in one single case, equal to the 1.2 V threshold. [38] Furthermore, those high values could only be achieved when the DP itself or some interfaces within the device were modified by, for example, substituting the organic HTM with an inorganic CuO 2 layer (1.198 V), [39] doping the perovskite with Li + (1.177 V), [40] making use of polymethyl methacrylate (PMMA) as a passivating capping layer between perovskite and a CE (1.180 V), [41] or by capping the perovskite layer with a 2D/3D mixed perovskite phase (1.18 V). [42] All these approaches aimed at improving the energy level alignment at the perovskite/HTM interface, which emphasizes its crucial role for boosting the V OC .…”