Investigating two-step MAPbI₃thin film formation during spin coating by simultaneousin situabsorption and photoluminescence spectroscopy

Abstract

Here we investigate the two-step MAPbI3 thin film formation during spin coating by simultaneous in situ absorption and photoluminescence spectroscopy.

Out-of-equilibrium processes in crystallization of organic-inorganic perovskites during spin coating

“…While there are several reports on phase transformations and identification 20,21,28,60 , detailed insights into the phenomena occurring at critical synthesis and phase transition stages are desirable. Importantly, the kinetic processes occurring during nucleation and dissolution-recrystallization have not been revealed in detail so far, and are the focus of the present study (Fig.…”

“…In the absence of an antisolvent, materials crystallizing out of a fluid precursor nucleate and crystallize in a broad time window, whereas the application of an orthogonal solvent is a physical route to temporally regulate supersaturation and initiate growth during material crystallization/formation. Accordingly, there are distinct differences in precursor chemistry and methods of physicochemical conversion between a one-step 9 and two-step 20,69 method which are typically discussed in the literature. The one-step method combines the organic (CH 3 NH 3 I) and inorganic precursors (PbI 2 ) in a solvent system (4:1 v:v DMF:DMSO) to afford a single colloidal precursor.…”

“…By utilizing the characteristically strong photoresponse of the materials, in situ optical methods 16,17 provide insight into the evolving optoelectronic properties of crystallizing perovskites. The interdependence of structure sizes and their optical response especially helps in understanding the evolving nature 18 of short-lived intermediates and the transformation kinetics 19,20 between material phases. Important considerations that have emerged from the above studies include the identification of the complex sol-gel 21 structures involved in the transformation, intermediate solventcomplex phases 22 involved during the assembly crystallization process 23 , the kinetics of their transformation to other phases [24][25][26][27] , the impact of varying the time of antisolvent dispensing 28 , the importance of thermal annealing processes 27,29,30 , and the sensitivity toward environmental conditions on the structure of processed thin films.…”

Investigating the Tetragonal‐to‐Orthorhombic Phase Transition of Methylammonium Lead Iodide Single Crystals by Detailed Photoluminescence Analysis

“…In general, it has been shown that self‐absorption effects can play an important role and need to be considered when analyzing measured PL spectra. [ 16–22 ] We recently demonstrated that self‐absorption can even lead to additional peaks in measured PL. With a relatively simple optical model it was possible to reproduce and analyze the additional peaks in the case of pure tetragonal or orthorhombic crystal phases.…”

Eye in the process: Formation of “triple cation” perovskite thin films rationalized by in-situ optical monitoring

“…Monitoring film formation in-situ during different processing stage enables the assessment of parameters affecting the thin film formation during processing and hence guide process optimization. [35][36][37] Valuable insight into different perovskite deposition strategies has been obtained from in-situ monitoring techniques such as grazing incidence wide-angle X-ray scattering (GIWAXS), [38][39][40][41] optical microscopy, 6,42 and absorption measurements 21,43,44 that provided critical insight guiding process optimization towards higher quality thin films and better device performance. These experiments are often carried out in specialized experimental setups.…”