Chinese scholars have made progress in the field of perovskite optoelectronic materials

Figure Perovskite thin film phase separation study
.
(a) Theoretical calculations based on first principles reveal the thermodynamic driving force of phase separation at the atomic/ionic scale; (b) Schelling models simulate the kinetic process of phase separation of thin film components from atomic to nanoscale; (c) Flight ion secondary mass spectrometry characterization of component phase separation at the micron scale

With the funding of the National Natural Science Foundation of China (approval numbers: 21975028, U21A20172, 22011540377), Professor Chen Qi's team of Beijing Institute of Technology has made progress in the field of perovskite optoelectronic materials research, and the related results are "Initializing film homogeneity to retard phase segregation.
" for stable perovskite solar cells", published online in the journal
Science on November 18, 2022.
Link to the paper: _istranslated="1">.

In recent years, solar cell devices based on organic-inorganic hybrid perovskites have achieved rapid development, and the highest photoelectric conversion efficiency reported so far has approached 26%.

Mixed-component perovskite materials can realize photoelectric performance regulation through reasonable chemical component design, thereby improving device efficiency and stability
.
However, due to the introduction of multiple components, the initial component distribution of the film will be uneven during the growth process of the material, resulting in problems such as phase separation, which not only affects the efficiency of the device, but also seriously affects the stability
of the device.

In this study, the thermodynamic driving force of spontaneous phase separation of mixed-component perovskite films was revealed, and the Schelling model (which originated in economics) was developed to simulate the dynamics of agglomeration of each group of dissociators, and the influence of the initial uniformity of the film on the performance attenuation of the device was clarified.
By preparing perovskite films with uniform distribution of starting components, the stability
of perovskite photovoltaic devices was significantly improved.
This study extends the Schelling model to unify atomic-scale ion movement and micro- and nano-scale phase separation kinetics under the same research paradigm (Figure).

This study provides a new idea for improving the stability of perovskite materials and photovoltaic devices, and also provides a theoretical basis
for the preparation of efficient and stable perovskite optoelectronic devices.