Ligand & band gap engineering: tailoring the protocol synthesis for achieving high-quality CsPbI₃ quantum dots

Abstract

<p>Hot-injection has become the most widespread method used for the synthesis of perovskite quantum dots (QDs) with enormous interest for application in optoelectronic devices.</p>

Photo-Induced Black Phase Stabilization of CsPbI3 QDs Films

“…This peak is not observed in the films, see Figure 4, indicating that this ligand is present as oleate species on the QDs. This is confirmed by the signals of the COO − group of the oleate [28], the symmetric and asymmetric stretching modes at 1409 and 1530 cm −1 , respectively. Oleylammonium can be spotted by a broad resonance centered at 3138 cm −1 corresponding to vibrations of ammonium groups, ν (N−H 3 + ) [14].…”

Tunable Carbon–CsPbI3 Quantum Dots for White LEDs

“…This fact is the consequence of the lower nonradiative recombination in CsPbI 3 PQDs as them become predominant in the solution. [ 21,26,28 ] All these results point to a low interaction between CQDs and PQDs beyond the light reabsorption process. Therefore, we conclude that by tuning the PQDs concentration in mixture with CQDs, the properties of the obtained white color can be tuned by the control of the ratio between both QDs.…”

Progress in halide-perovskite nanocrystals with near-unity photoluminescence quantum yield

“…Halide PNCs (see Glossary) with a general APbX 3 formula (A= Cs + , FA + ; formamidinium, MA + ; methylammonium, X = Cl, Br, I, and corresponding mixtures) have received growing interest in optoelectronics, photovoltaics, and analogous solar-driven processes such as photocatalysis, greatly extending their applicability in recent years. The outstanding photophysical properties of PNCs, such as tunable band gaps covering a broad UV-Vis-IR region [1,2], narrow full width at half maximum (FWHM) PL [3], stability under ambient conditions [4,5], versatile surface chemistry, and facile processability [6][7][8], have triggered diverse studies to prepare PNC colloidal solutions for efficient multicolor light-emitting diodes (LEDs) [9][10][11][12][13], perovskite quantum dot solar cells (QDSSCs) [14][15][16][17][18], oxidation/reduction reactions in model systems [2,19,20], solar fuel generation [21,22], and solar synthesis [23]. Since the first report provided by Perez Prieto and coworkers [24] and Kovalenko and coworkers [1] on the synthesis of CH 3 NH 3 PbBr 3 and CsPbX 3 PNCs in 2014 and 2015, respectively, research in the field of PNCs has demonstrated that improvement of the above properties is defined by the quality of the synthesized PNCs, established by estimating their PLQY [5].…”

“…Since the first report provided by Perez Prieto and coworkers [24] and Kovalenko and coworkers [1] on the synthesis of CH 3 NH 3 PbBr 3 and CsPbX 3 PNCs in 2014 and 2015, respectively, research in the field of PNCs has demonstrated that improvement of the above properties is defined by the quality of the synthesized PNCs, established by estimating their PLQY [5]. After 6 years of continuous studies on the intrinsic properties of PNCs, it has been deduced that these materials can be denoted as 'high quality' when their PLQY is >90% [5,25,26]. This means that the radiative recombination mechanism requires the material to be as trap free as possible and mostly dictates the optoelectronic features of PNCs [27].…”

“…The generation of these defects has been also associated with difficulties in stabilizing the PNCs. During PNC preparation, OA and OLA are transformed into oleylammonium oleate, which is the main species for PNC stabilization [5,45,46]. Oleylammonium cations bind to halide anions of the PNCs as ionic pairs, promoting surface passivation.…”