Superior stability for perovskite solar cells with 20% efficiency using vacuum co-evaporation

Abstract

Chemical composition and film quality are two key figures of merit for large-area high-efficiency perovskite solar cells. To date, all studies on mixed perovskites have used solution-processing, which results in imperfect surface coverage and pin-holes generated during solvent evaporation, execrably influencing the stability and efficiency of perovskite solar cells. Herein, we report our development using a vacuum co-evaporation deposition method to fabricate pin-hole-free cesium (Cs)-substituted perovskite films with complete surface coverage. Apart from the simplified procedure, the present method also promises tunable band gap, reduced trap-state density and longer carrier lifetime, leading to solar cell efficiency as high as 20.13%, which is among the highest reported for planar perovskite solar cells. The splendid performance is attributed to superior merits of the Cs-substituted perovskite film including tunable band gap, reduced trap-state density and longer carrier lifetime. Moreover, the Cs-substituted perovskite device without encapsulation exhibits significantly higher stability in ambient air compared with the single-component counterpart. When the Cs-substituted perovskite solar cells are stored in dark for one year, the PCE remains at 19.25%, degrading only 4.37% of the initial efficiency. The excellent stability originates from reduced lattice constant and relaxed strain in perovskite lattice by incorporating Cs cations into the crystal lattice, as demonstrated by the positive peak shifts and reduced peak width in X-ray diffraction analysis.

Record Efficiency Stable Flexible Perovskite Solar Cell Using Effective Additive Assistant Strategy

“…Flexible photovoltaic cells have great potential applications in numerous emerging fields, such as wearable electronics, portable chargers, remote power, automobiles, flying objects, etc., owing to their apparent advantages in lightweight, continuous roll‐to‐roll processability, tolerance in flexing, ease in storage, handling, transportation, and installation, etc . Since the organometal halide perovskite material was used in solar cells, remarkable achievements have been made due to its excellent properties, including defect tolerance, tunable bandgap, high charge carrier mobility, long electron–hole diffusion length, extremely low trap density, small exciton‐binding energy, etc . Especially, the characteristics of high power conversion efficiency (PCE), low‐temperature solution processing, and large optical absorption coefficient make it possible to develop thin film perovskite solar cells (PSCs) for low cost, lightweight, and flexible applications …”

Extending lead-free hybrid photovoltaic materials to new structures: thiazolium, aminothiazolium and imidazolium iodobismuthates

“…9) in 2013 to over 22% today, 10 as well as much increased stability under humidity and oxygen. [11][12][13][14] In addition, lead-halide perovskites have also been studied in other devices including capacitors, 15 batteries 16 and the integration of a solar cell and supercapacitor. 17 However, one intrinsic limitation of these perovskite materials is the toxicity of lead, which raises environmental and health concerns and thus hinders future large-scale implementation.…”

Doping Strategy for Efficient and Stable Triple Cation Hybrid Perovskite Solar Cells and Module Based on Poly(3‐hexylthiophene) Hole Transport Layer

“…At V 2 , when the bias voltage exceeded the kink point corresponding to trap‐filled limit voltage ( V TFL ), the current quickly increased, indicating that the trap states were completely filled. The dark JV results are in good agreement with EIS, demonstrating that the photovoltaic improvement by cobalt doping in the P3HT via notably decrease in charge recombination.…”