# In Situ Growth Method for Large-Area Flexible Perovskite Nanocrystal Films

## TL;DR

A new method for making large-area perovskite nanocrystal films is developed, improving efficiency and scalability for optoelectronic applications.

## Contribution

A scalable in situ growth method for CsPbBr3 nanocrystal films with enhanced luminous efficiency through magnesium ion incorporation.

## Key findings

- CsPbBr3 nanocrystal films were fabricated over 5.5 cm × 5.5 cm with controlled thickness and uniformity.
- Magnesium ion addition improved crystallization and surface defect passivation, boosting luminous efficiency.
- Integration with a silicon photodiode increased responsivity at 365 nm UV wavelength from 1.68 × 10−2 A/W to 3.72 × 10−2 A/W.

## Abstract

Metal halide perovskites have shown unique advantages compared with traditional optoelectronic materials. Currently, perovskite films are commonly produced by either multi-step spin coating or vapor deposition techniques. However, both methods face challenges regarding large-scale production. Herein, we propose a straightforward in situ growth method for the fabrication of CsPbBr3 nanocrystal films. The films cover an area over 5.5 cm × 5.5 cm, with precise thickness control of a few microns and decent uniformity. Moreover, we demonstrate that the incorporation of magnesium ions into the perovskite enhances crystallization and effectively passivates surface defects, thereby further enhancing luminous efficiency. By integrating this approach with a silicon photodiode detector, we observe an increase in responsivity from 1.68 × 10−2 A/W to 3.72 × 10−2 A/W at a 365 nm ultraviolet wavelength.