Film-through large perovskite grains formation via a combination of sequential thermal and solvent treatment

Abstract

Organic-inorganic halide perovskites have recently attracted strong research interest for fabrication of high-performance, lowcost photovoltaic devices. Recently, we reported a highly reproducible procedure to fabricate high-performance organic-inorganic halide perovskite solar cells. This procedure, based on a onestep, solvent-induced, fast deposition-crystallization method, involves the use of sec-butyl alcohol as a new solvent to induce the CH 3 NH 3 PbI 3 fast crystallization deposition. In the present study, we propose a reproducible fabrication method to prepare both flat and large-grain perovskite film by adding a pre-annealing step to strengthen the perovskite nucleation, aiming to facilitate the excess CH 3 NH 3 I and solvent removal in the sec-butyl alcohol soaking process, in which all films with thickness between 420 nm and 1 mm performed uniformly. The best performing planar device obtained with this procedure had an efficiency of 17.2% under AM 1.5G illumination and an average power conversion efficiency of 16.2 AE 0.5%. We also analyzed the efficiency of halide perovskite planar solar cells as a function of the perovskite film thickness; the efficiency dropped only slightly to 15.7% when the perovskite film thickness was increased to 1 mm.

Role of Microstructure in Oxygen Induced Photodegradation of Methylammonium Lead Triiodide Perovskite Films

“…A histogram of the PCE derived from measurement of more than 100 devices, as well as the statistics of the photovoltaic parameters are presented in Figure S1 of the Supporting Information. [31][32][33] Conversely, the SEM cross-section of the sol-eng film shows that the film consists of multiple grains which are larger at the interface with PEDOT:PSS and smaller at the film surface. The J-V characteristics exhibit very little hysteresis and a stable power output ( Figure S2, Supporting Information) which can be attributed to the use of PCBM as an electron extraction layer.…”

“…[29,30] Scanning electron microscopy (SEM) images of the layer surface of freshly prepared perovskite films on ITO/PEDOT:PSS in Figure 1b,c reveal that the average grain size for PbAc 2 layers is bigger (≈147 nm) as compared to the sol-eng layers (≈99 nm), while the root-meansquared (RMS) surface roughness ( Figure S3, Supporting Information) is fairly small for both (9.34 and 12.84 nm for PbAc 2 and sol-eng, respectively). [40][41][42] Additional solvent/air annealing steps or the use of additives in the precursor solution have been shown to improve the film morphology and consequently the efficiency of devices using PEDOT:PSS as hole transporting layer (HTL), [31,[42][43][44] but we deliberately chose the nonmodified layer and obtain efficiencies comparable to similar devices in earlier studies. [31][32][33] Conversely, the SEM cross-section of the sol-eng film shows that the film consists of multiple grains which are larger at the interface with PEDOT:PSS and smaller at the film surface.…”

Semimetal–Semiconductor Transitions for Monolayer Antimonene Nanosheets and Their Application in Perovskite Solar Cells

“…To further investigate the interfacial effect of SANs on hole extraction behavior, planar inverted PVSCs were fabricated using the device architecture of indium tin oxide (ITO)/PTAA/SANs/CH 3 NH 3 PbI 3 /[6,6]‐phenyl C61 butyric acid methyl ester (PCBM)/Bphen/Al (Figure S17a, Supporting Information). Active perovskite layer (CH 3 NH 3 PbI 3 ) was deposited by a facile one‐step method . PTAA and Bphen‐modified PC 61 BM were employed as HTL and electron transport layer, respectively.…”

Suppressed Decomposition of Perovskite Film on ZnO Via a Self‐Assembly Monolayer of Methoxysilane

“…Perovskite films with small grain size contains more grain boundary and exhibit much more surface defects, deteriorating the photovoltaic performance of PSCs . Solvent annealing method is widely used to increase the grain size of perovskite crystal, but it is complicate due to the introduced solvent . To simplify the solvent annealing process, a self‐form solvent annealing (SFSA) method has been introduced here.…”