Trapping light, revealing properties: Laser trapping as a powerful tool for photoluminescence spectroscopy

Laser trapping, a non-contact technique for manipulating microscopic objects, has gained prominence in scientific research. When coupled with fluorescence spectroscopy, it offers a powerful tool for exploring material properties. This study demonstrates the application of laser trapping in the crystallization of MAPbBr₃ perovskites and its simultaneous use for photoluminescence imaging. MAPbBr₃ perovskites are a class of materials with exceptional optical properties, making them attractive for various optoelectronic applications. However, conventional excitation methods using UV light can lead to phase segregation and mechanical distortion of these materials. Two-photon excitation, on the other hand, offers advantages such as deeper penetration and reduced scattering interference. In this research, we utilize a 1064 nm continuous wave laser for both trapping and excitation purposes. The MAPbBr₃ perovskite, with its absorption band ranging from 400 to 540 nm, exhibits two-photon excitation at 532 nm. By focusing the laser beam at the air-solution interface, we successfully crystallize MAPbBr₃ perovskites from an unsaturated precursor solution. Simultaneously, the same laser source is used for photoluminescence imaging, allowing for real-time analysis of the crystal's emission properties. This approach eliminates the need for additional excitation sources and simplifies the experimental setup. The combination of laser trapping and two-photon excitation opens up new possibilities for studying perovskite materials. It provides a gentle and non-invasive method for manipulating and characterizing hybrid perovskites materials, paving the way for advancements in various fields such as optoelectronics and energy harvesting.