Imaging of Perovskite Photoactive Layer Cross-Section by Atomic Force Microscopy

The volume structure of photoactive layer has critical influence on perovskite solar cell performance and life time. In this study the perovskite photoactive layer cross-section was prepared by using Focused Ion Beam (FIB) and imaged by using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) methods (Fig. 16). Two different types of perovskite layers were investigated: FAPbBr3 and MAPbBr3

Crystal engineering approach for fabrication of inverted perovskite solar cell in ambient conditions

In this paper, we demonstrate the high potentialities of pristine single-cation and mixed cation/anion perovskite solar cells (PSC) fabricated by sequential method deposition in p-i-n planar architecture (ITO/NiOX/Perovskite/PCBM/BCP/Ag) in ambient conditions. We applied the crystal engineering approach for perovskite deposition to control the quality and crystallinity of the light-harvesting film. The formation of a full converted and uniform perovskite absorber layer from poriferous pre-film on a planar hole transporting layer (HTL) is one of the crucial factors for the fabrication of high-performance PSCs. We show that the in-air sequential deposited MAPbI3-based PSCs on planar nickel oxide (NiOX) permitted to obtain a Power Conversion Efficiency (PCE) exceeding 14% while the (FA,MA,Cs)Pb(I,Br)3-based PSC achieved 15.6%. In this paper we also compared the influence of transporting layers on the cell performance by testing material depositions quantity and thickness (for hole transporting layer), and conditions of deposition processes (for electron transporting layer). Moreover, we optimized second step of perovskite deposition by varying the dipping time of substrates into the MA(I,Br) solution. We have shown that the layer by layer deposition of the NiOx is the key point to improve the efficiency for inverted perovskite solar cell out of glove-box using sequential deposition method, increasing the relative efficiency of +26% with respect to reference cells

Imaging of Perovskite Photoactive Layer Cross-Section by Atomic Force Microscopy

The volume structure of photoactive layer has critical influence on perovskite solar cell performance and life time. In this study the perovskite photoactive layer cross-section was prepared by using Focused Ion Beam (FIB) and imaged by using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) methods (Fig. 16). Two different types of perovskite layers were investigated: FAPbBr3 and MAPbBr3

Copper Iodide Interlayer for Improved Charge Extraction and Stability of Inverted Perovskite Solar Cells

Nickel oxide (NiO) is one of the most promising and high-performing Hole Transporting Layer (HTL) in inverted perovskite solar cells due to ideal band alignment with perovskite absorber, wide band gap, and high mobility of charges. At the same time, however, NiO does not provide good contact and trap-free junction for hole collection. In this paper, we examine this problem by developing a double hole transport configuration with a copper iodide (CuI) interlayer for efficient surface passivation. Transient photo-current (TPC) measurements showed that Perovskite/HTL interface with CuI interlayer has an improved hole injection; CuI passivation reduces the concentration of traps and the parasitic charge accumulation that limits the flow of charges. Moreover, we found that CuI protect the HTL/perovskite interface from degradation and consequently improve the stability of the cell. The presence of CuI interlayer induces an improvement of open-circuit voltage VOC (from 1.02 V to 1.07 V), an increase of the shunt resistance RSH (100%), a reduction of the series resistance RS (−30%), and finally a +10% improvement of the solar cell efficiency