Herein, new types of zero‐dimensional (0D) perovskites (PA6InCl9 and PA4InCl7) with blue room‐temperature phosphorescence (RTP) were obtained from InCl3 and aniline hydrochloride. These are highly sensitive to external light and force stimuli. The RTP quantum yield of PA6InCl9 can be enhanced from 25.2 % to 42.8 % upon illumination. Under mechanical force, PA4InCl7 exhibits a phase transform to PA6InCl9, thus boosting ultralong RTP with a lifetime up to 1.2 s. Furthermore, white and orange pure RTP with a quantum yield close to 100 % can be realized when Sb3+ was introduced into PA6InCl9. The white pure phosphorescence with a color‐rendering index (CRI) close to 90 consists of blue RTP of PA6InCl9 and orange RTP of Sb3+. Thus, this work not only overcomes long‐standing problems of low quantum yield and short lifetime of blue RTP, but also obtains high‐efficiency white RTP. It provides a feasible method to realize near‐unity quantum efficiency and has great application potential in the fields of optical devices and smart materials.

Herein, an organic fluorophore termed NLAC is introduced into 2D hybrid perovskites with wide band gap (>3.54 eV) to give a green emission with quantum yield up to 81%. The highly efficient luminescence is ascribed to avoiding the aggregation of NLAC and formation of an inorganic free exciton which is easy to thermally quench. On this basis, a new strategy to generate efficient white emission with afterglow has been proposed by codoping a short-wavelength fluorophore and long-wavelength phosphor into 2D organic− inorganic hybrid perovskites (OIHPs). As a result, a single-component white-light-emitting material PEPC-3N based on NLAC with CIE of (0.33, 0.36) and quantum yield up to 43% can be obtained. Interestingly, PEPC-3N shows a dual-color organic afterglow and excitation-wavelength-dependent emission, consequently forming a switch between green fluorescence and yellow afterglow. This unique performance indicates PEPC-3N has huge potential in afterglow WLEDs and information storage.

2D organic–inorganic hybrid perovskites (OIHPs) show obvious advantages in the field of optoelectronics due to their high luminescent stability and good solution processability. However, the thermal quenching and self‐absorption of excitons caused by the strong interaction between the inorganic metal ions lead to a low luminescence efficiency of 2D perovskites. Herein, a 2D Cd‐based OIHP phenylammonium cadmium chloride (PACC) with a weak red phosphorescence (ΦP < 6%) at 620 nm and a blue afterglow is reported. Interestingly, the Mn‐doped PACC exhibits very strong red emission with nearly 200% quantum yield and 15 ms lifetime, thus resulting in a red afterglow. The experimental data prove that the doping of Mn2+ not only induces the multiexciton generation (MEG) process of the perovskite, avoiding the energy loss of inorganic excitons, but also promotes the Dexter energy transfer from organic triplet excitons to inorganic excitons, thus realizing the superefficient red‐light emission of Cd2+. This work suggests that guest metal ions can induce host metal ions to realize MEG in 2D bulk OIHPs, which provides a new idea for the development of optoelectronic materials and devices with ultrahigh energy utilization.

Organic-inorganic hybrid metal halides have attracted intensive attention because of their unique electronic structure and solution processability. They have rigid micro/nano structure and heavy atom effect, which has obvious advantages...

Herein, new types of zero‐dimensional (0D) perovskites (PA6InCl9 and PA4InCl7) with blue room‐temperature phosphorescence (RTP) were obtained from InCl3 and aniline hydrochloride. These are highly sensitive to external light and force stimuli. The RTP quantum yield of PA6InCl9 can be enhanced from 25.2 % to 42.8 % upon illumination. Under mechanical force, PA4InCl7 exhibits a phase transform to PA6InCl9, thus boosting ultralong RTP with a lifetime up to 1.2 s. Furthermore, white and orange pure RTP with a quantum yield close to 100 % can be realized when Sb3+ was introduced into PA6InCl9. The white pure phosphorescence with a color‐rendering index (CRI) close to 90 consists of blue RTP of PA6InCl9 and orange RTP of Sb3+. Thus, this work not only overcomes long‐standing problems of low quantum yield and short lifetime of blue RTP, but also obtains high‐efficiency white RTP. It provides a feasible method to realize near‐unity quantum efficiency and has great application potential in the fields of optical devices and smart materials.