Morphology Engineering: A Route to Highly Reproducible and High Efficiency Perovskite Solar Cells

Abstract

Despite the rapid increase in the performance of perovskite solar cells, they still suffer from low lab-to-lab or people-to-people reproducibility. Aiming for a universal condition to high performance devices, we investigated the morphology evolution of the composite perovskite by tuning annealing temperature and precursor concentration of the perovskite film. Here we introduce thermal annealing as a powerful tool to generate a well controlled excess of PbI 2 in the perovskite formulation and show that this benefits the photovoltaic performance. We demonstrated the correlation between the film microstructure and electronic property and device performance. An optimized average grain size/thickness aspect ratio of the perovskite crystallite is identified, which brings about a highly 2 reproducible power conversion efficiency (PCE) of 19.5%, with a certified value of 19.08%.Negligible hysteresis and outstanding morphology stability are observed with these devices. These findings lay the foundation for further boosting the PCE of PSC and can be very instructive in fabrication high quality perovskite films for a variety of applications, such as light-emitting diodes, field-effect transistors and photo-detectors, etc.

Methodologies toward Highly Efficient Perovskite Solar Cells

“…In‐depth study of electrical defects, which are known to limit device performance, may be important in understanding the photophysics of devices. Although the correlation between material quality and device performance has been extensively studied in general optoelectronic materials, in‐depth understanding of the crystallization rate and growth mechanism of perovskite, particularly the continuous conversion of the precursor solution to the solid phase, has not been unveiled. Accordingly, a comprehensive study of perovskite crystallization kinetics and morphological evolution from the original precursor solution to crystalline solid phase is important to further improve perovskite quality and eventual device performance.…”

Regulated Film Quality with Methylammonium Bromide Addition in a Two‐Step Sequential Deposition to Improve the Performance of Perovskite Solar Cells

“…As a promising contender for many developed photovoltaic (PV) technologies (such as silicon and dye‐sensitized solar cells), perovskite solar cells (PSCs) have led to unprecedented extensive research and achieved extraordinary progress to enhance the power conversion efficiency (PCE) and stability . To date, the certified record PCE of PSCs is 22.1 % .…”

“…As ap romising contender for many developed photovoltaic (PV) technologies( such as silicon and dye-sensitized solar cells), perovskite solar cells (PSCs) have led to unprecedented extensive research and achieved extraordinary progress to enhance the power conversion efficiency (PCE) and stability. [1][2][3][4][5][6][7][8] To date,t he certified record PCE of PSCs is 22.1 %. [9,10] Several photophysical properties of perovskite materials,s uch as the tunable band gap,l ong carrier transport length, and high light absorption efficiency,a re mainly responsible for this phenomenon.…”

Interfacial Sulfur Functionalization Anchoring SnO2 and CH3NH3PbI3 for Enhanced Stability and Trap Passivation in Perovskite Solar Cells

“…[8] So far,t here has been av ariety of organic interfacial modulationt echniques to mitigate the influence of defects on the charge transfer kinetics and energetically favorable rapid nucleation, such as use of amino acids and self-assembled monolayers (SAMs). [15,16] Electronic coupling betweent he SnO 2 ETL andp erovskite allows for efficient electron extraction and this reduces chargea ccumulation near the interface, [11,17] which results in strongh ysteresis behavior.T o Trap states at the interface or in bulk perovskite materials critically influence perovskite solar cells performance and longterm stability.H ere, as trategy for efficiently passivatingc harge traps and mitigating interfacial recombination by SnO 2 surface sulfur functionalization is reported, which utilizes xanthate decomposition on the SnO 2 surface at low temperature. [12,13] However,t hese approaches involved multiple and complex fabrication processes or using complicated organic molecules, which is not favorable in terms of fabrication cost.…”