CsPbX3 perovskite nanocrystals (NCs) are promising light‐emitting materials that have gained significant attention over the past few years. The synthesis of CsPbX3 NCs is usually performed in an inert environment under high temperature conditions; however, this requirement hinders commercial development. Low‐temperature preparation of CsPbX3 NCs with rationally designed surface ligands is crucial to the performance and stability of CsPbX3 light‐emitting diodes (LEDs). In this work, short‐chain ligand‐anchored CsPbBr3 NCs in ambient conditions at room temperature are synthesized and a ligand‐exchange strategy is employed, using longer‐chain acid/amine ligand pairs, resulting in the dramatic improvement of performance and stability of CsPbBr3 NCs LEDs. It is found that CsPbBr3 NCs anchored by oleic acid and oleylamine complex ligands result in the best LED performance, with the maximum luminance of 5033 Cd m−2, current efficiency of 18.6 Cd A−1, external quantum efficiency of 5.4%, turn‐on voltage of 3.2 V, and the best thermal stability under ambient conditions.
CsPbX 3 nanocrystal (NC)-based blue perovskite light-emitting diodes (PeLEDs) are still in a backward position while their green and red counterparts have achieved significant progress in the past few years. The emission spectrum of perovskite NCs can be manipulated via the ratio control of halides in precursor or halogen exchange of NCs. Herein, CsPbBr x Cl 3−x NCs are synthesized in ambient condition. With tetrabutylammonium p-toluenesulfonate (TBSA) added as the ligand during the purification process of assynthesized perovskite NCs, bromine in NCs is substituted by chlorine and the spectrum undergoes a blue shift, whereas chlorine is exchanged by bromine in NCs and the spectrum undergoes a red shift by introducing sodium dodecylbenzenesulfonate (SDSA) as the ligand. The origin for halogen exchange can be attributed to the synergistic effects of the anion and cation of benzenesulfonates. The photoluminescence quantum yield (PLQY) of NCs increases from 7% to 81% due to the effective passivating effects of the strong ionic sulfonate heads, and the blue PeLEDs prepared by this method show a promising external quantum efficiency of 2.6%. Our work provides a new approach into spectral tuning of efficient blue PeLEDs.
Inorganic perovskite solar cells (PSCs) have witnessed great progress in recent years due to their superior thermal stability. As a representative, CsPbI
2
Br is attracting considerable attention as it can balance the high efficiency of CsPbI
3
and the stability of CsPbBr
3
. However, most research employs doped charge transport materials or applies bilayer transport layers to obtain decent performance, which vastly complicates the fabrication process and scarcely satisfies the commercial production requirement. In this work, all‐layer‐doping‐free inorganic CsPbI
2
Br PSCs using organic ligands armored ZnO as the electron transport materials achieve an encouraging performance of 16.84%, which is one of the highest efficiencies among published works. Meanwhile, both the ZnO‐based CsPbI
2
Br film and device show superior photostability under continuous white light‐emitting diode illumination and improved thermal stability under 85 °C. The remarkable enhanced performance arises from the favorable organic ligands (acetate ions) residue in the ZnO film, which not only can conduce to maintain high crystallinity of perovskite, but also passivate traps at the interface through cesium/acetate interactions, thus suppressing the photo‐ and thermal‐ induced perovskite degradation.
p-Type semiconductor PBDB-T and its derivatives have been explored as dopant-free hole transport materials for CsPbI2Br inorganic perovskite solar cells, with PBDB-T-Si enabling a PCE of 15.6% and FF exceeding 84%.
Metal
halide perovskites are considered to be the new generation
of semiconductors for optoelectronic devices because of their low
material cost and superior optical and electrical properties, such
as narrow emission line width, tunable emission wavelength, and high
charge carrier mobility. However, the morphological and energetic
defects of perovskites grown from solution casting hinder the maximum
achievable performance of devices. Additive strategy has been demonstrated
as a facile and effective method to acquire high quality perovskite
films. In this work, we introduce three ionic additives, namely, tetrabutylammonium
bromide (TBABr), benzyltriethylammonium bromide (BTEABr), and benzyltributylammonium
bromide (BTBABr), into CH3NH3Br3 (MAPbBr3) precursor solution, respectively, to prepare pinhole-free
perovskite films with reduced defect density. Perovskite light-emitting
diodes (PeLEDs) incorporating BTBABr-modified MAPbBr3 emitter
exhibits a significantly reduced turn-on voltage from 4.6 to 2.6 V
and improved maximum luminance and current efficiency of 23646 cd/m2 and 3.39 cd/A compared with those of 3926 cd/m2 and 0.27 cd/A of pristine MAPbBr3-based device.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.