Single‐component materials with efficient, stable, and tunable cold/warm white‐light emission are ideal candidates for lighting applications, which can overcome the problems of different deterioration rates and reabsorption effect in conventional mixed‐phosphors strategy. Efficient white phosphors based on double halide perovskite have been reported via manipulating the parity transitions recently. However, the emission wavelength is nonadjustable. Herein, a lead‐free double perovskite Cs2Zr1−xTexCl6 that exhibits efficient and stable white‐light emission is reported. The introduction of Te4+ results in bright self‐trapped exciton (STE) emission, which endows Cs2ZrCl6 matrix with multiple luminescent centers. Efficient white luminescence with tunable color temperature and high photoluminescence quantum yield (PLQY) of 61.5% (under 254 nm, CCT = 4039 K) and 96.1% (under 365 nm, CCT = 3313 K) is achieved. Efficient energy transfer between multiple luminescent centers and appropriate doping concentrations are the key points to achieve such highly efficient and tunable white emission. The as‐synthesized Cs2Zr1−xTexCl6 composites exhibit a robust stability against heat, ultraviolet light, and environmental oxygen/moisture, which show little spectra variation with less than ≈20% efficiency loss after 980 h testing even under high temperature and UV light. These results indicate Cs2Zr1−xTexCl6 are promising single‐component white‐light‐emitting phosphors for next‐generation lighting and display technologies.
Metal
halide perovskites have been demonstrated as potential X-ray
detection materials due to their high defect tolerance, large diffusion
length, and high attenuation efficiency. X-ray detectors based on
hot-pressed perovskite wafers are investigated intensively recently
because of the convenience of scalable fabrication. However, in spite
of the large crystal size within wafers, the prepared detectors usually
suffer from severe ion migration and current drift under both dark
and bright states. In this work, ethylenediamine dihydroiodate (EDDI)
was introduced as a strong surface passivation agent, which compensated
for the surface iodide vacancy successfully. The ion migration in
optimal MAPbI3@EDDI wafer is significantly suppressed,
which is manifested by increased migration activation energy and stable
current under high bias for 10 h. Moreover, the introduction of EDDI
also reduced the dark current, contributing a high on–off ratio
and a champion sensitivity of 8291.22 μC Gyair
–1 cm–2. A low detection limit of
340 nGyair s–1 is also obtained, which
is much lower than that of commercial X-ray detectors. Besides, the
as-fabricated X-ray detector can endure long-term operation with flat
current under a high bias of 20 V. This work provides a route for
the performance improvement of perovskite wafer-based X-ray detectors.
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