10.1021/acsanm.9b01857.s001 Anna Jancik Prochazkova Anna Jancik Prochazkova Yolanda Salinas Yolanda Salinas Cigdem Yumusak Cigdem Yumusak Markus Clark Scharber Markus Clark Scharber Oliver Brüggemann Oliver Brüggemann Martin Weiter Martin Weiter Niyazi Serdar Sariciftci Niyazi Serdar Sariciftci Jozef Krajcovic Jozef Krajcovic Alexander Kovalenko Alexander Kovalenko Controlling Quantum Confinement in Luminescent Perovskite Nanoparticles for Optoelectronic Devices by the Addition of Water American Chemical Society 2020 32 mol equiv nanoparticle exhibit chemical tunability solution Controlling Quantum Confinement perovskite lattice growth photoluminescence quantum yields method metal halide PNPs PLQY preparation bromide Luminescent Perovskite Nanoparticles quantum confinement effect optoelectronic devices 2020-01-17 16:34:19 Journal contribution https://acs.figshare.com/articles/journal_contribution/Controlling_Quantum_Confinement_in_Luminescent_Perovskite_Nanoparticles_for_Optoelectronic_Devices_by_the_Addition_of_Water/11638173 Here, a simple method for controlling the size of the perovskite nanoparticles (PNPs) during preparation is reported. Metal halide PNPs have great potential for application in optoelectronic devices, such as light-emitting diodes, lasers, photodetectors, etc. They have exceptionally high photoluminescence quantum yields (PLQYs) and exhibit chemical tunability for versatile modifications of the perovskite structural composition, enabling the synthesis of nanoparticles with controlled size, shape, and optical properties. In this work, methylammonium lead bromide PNPs were prepared using a hygroscopic stabilizing ligand, tert-butoxycarbonyl-Lysine (tboc-Lysine). Water was used as an additive in the precursor solution, which resulted in the formation of highly mobile species and, thus, the nhancement of perovskite lattice growth. This method allowed the preparation of PNPs with controlled size between 4 and 7 nm. The quantum confinement effect led to a fine-tuned optical band gap of the nanoparticles. Increasing the amount of water added from 0 to 32 mol equiv with respect to Lead­(II) bromide (PbBr<sub>2</sub>) increased the PLQY to 70% in colloidal solutions and to 87% in thin films. Therefore, because of control over the size and high luminescent yields, the above-mentioned nanoparticles are targeted for use in optoelectronic devices.