Recently, perovskite solar cells (PSCs) have been rapidly developed, counting as the most promising alternative to the Si solar cells. The fabrication of perovskite films with controlled crystallinity and grain size is critical for highly efficient and stable solar cells. In this work, thiourea (TU) serving as a Lewis acid‐base adduct is introduced into the CH3NH3PbI3 precursor. A smooth and large grained perovskite crystal is obtained without the intermediate phase PbI2 · SC(NH2)2 using the ideal thiourea amount. Thiourea, through forming MAI · PbI2 · DMSO · thiourea in perovskite precursor solution, significantly impacts the perovskite crystallinity and morphology, as proved using X‐ray diffraction patterns and infrared spectroscopy. Light harvesting, suppressed defect state, and enhanced charge separation and transport of the perovskite absorber layer are improved. The optimum performance of perovskite solar cells with TU demonstrated a power conversion efficiency (PCE) of 19.80%, an average steady‐state PCE of 18.60% and potent stability under ambient air.

Novel white light emitting diodes (LEDs) with environmentally friendly dual emissive quantum dots (QDs) as single color-converters are one of the most promising high-quality solid-state lighting sources for meeting the growing global demand for resource sustainability. A facile method was developed for the synthesis of the bright green-red-emitting Mn and Cu codoped Zn-In-S QDs with an absorption bangdgap of 2.56 eV (485 nm), a large Stokes shift of 150 nm, and high emission quantum yield up to 75%, which were suitable for warm white LEDs based on blue GaN chips. The wide photoluminescence (PL) spectra composed of Cu-related green and Mn-related red emissions in the codoped QDs could be controlled by varying the doping concentrations of Mn and Cu ions. The energy transfer processes in Mn and Cu codoped QDs were proposed on the basis of the changes in PL intensity and lifetime measured by means of steady-state and time-resolved PL spectra. By integrating these bicolor QDs with commercial GaN-based blue LEDs, the as-fabricated tricolor white LEDs showed bright natural white light with a color rendering index of 95, luminous efficacy of 73.2 lm/W, and color temperature of 5092 K. These results indicated that (Mn,Cu):Zn-In-S/ZnS QDs could be used as a single color-converting material for the next generation of solid-state lighting.

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