Solvatochromic Photoluminescent Effects in All‐Inorganic Manganese(II)‐Based Perovskites by Highly Selective Solvent‐Induced Crystal‐to‐Crystal Phase Transformations

Abstract

The development of lead‐free perovskite photoelectric materials has been an extensive focus in the recent years. Herein, a novel one‐dimensional (1D) lead‐free CsMnCl3(H2O)2 single crystal is reported with solvatochromic photoluminescence properties. Interestingly, after contact with N,N‐dimethylacetamide (DMAC) or N,N‐dimethylformamide (DMF), the crystal structure can transform from 1D CsMnCl3(H2O)2 to 0D Cs3MnCl5 and finally transform into 0D Cs2MnCl4(H2O)2. The solvent‐induced crystal‐to‐crystal phase transformations are accompanied by loss and regaining of water of crystallization, leading to the change of the coordination number of Mn2+. Correspondingly, the luminescence changes from red to bright green and finally back to red emission. By fabricating a test‐paper containing CsMnCl3(H2O)2, DMAC and DMF can be detected quickly with a response time of less than one minute. These results can expand potential applications for low‐dimensional lead‐free perovskites.

Cs2MnCl4:Eu2+: A Near-Violet Light-Triggered Single-Component White Light Emitter

“…To provide a more intuitive explanation for this phenomenon, we assessed the crystal field strength of Cs 2 MnCl 4 :Eu 2+ and Cs 2 MnCl 4 (H 2 O) 2 using the following formula D q = Z e 2 r 4 6 R 5 where D q is the magnitude of the 5d energy level separation, Z is the charge or valence of the anion, e is the charge of an electron, r is the radius of the d wave function, and R is the bond length. According to this formula, the ratio of the crystal field intensity of Mn 2+ site of Cs 2 MnCl 4 :Eu 2+ and Cs 2 MnCl 4 (H 2 O) 2 (with an emission wavelength of 615 nm) is approximately 5.95:8.95. , This finding suggests that the blue shift in luminescence is attributable to a reduction in the crystal field. Table 1 shows a performance comparison of some single-component halide perovskites.…”

“…Because the 3d electrons of Mn 2+ are the outermost electrons, the energy level splitting energy of 3d 5 of Mn 2+ in crystals is calculated and deduced by the Tanabe−Sugano diagram (Figure S5). 31 According to the general theory of d-ion emission, the emission peak position of Mn 2+ can be determined by the crystal field strength. According to the separation degree of T and A, the emission of Mn 2+ can be adjusted from the blue to the near-infrared region.…”

Stepwise Crystalline Structural Transformation in 0D Hybrid Antimony Halides with Triplet Turn-on and Color-Adjustable Luminescence Switching

“…Despite high expectation, the vast majority of smart luminescent LDHPs overwhelmingly dependent on the slight shift of emission wavelength with low contrast acting as color-tunable PL switch, few approach has shown to realize PL off–on switch [ 42 – 44 ]. The research deficiency attracts intensive attention to further explore more smart fluorescence switch by finely tuning the local structure of LDHP.…”

Acidochromic organic photovoltaic integrated device

“…At present, tremendous efforts have been dedicated to improving OSC performance with power conversion efficiency (PCE) of up to 19%, suggesting the promise of commercialization of OSCs in the near future [6][7][8][9][10][11][12][13]. Beyond that, the future organic photovoltaic device could be smarter with multifunction that can meet diverse requirements with the ability of monitoring various environmental conditions such as UV exposure and acid rain pollution [14][15][16]. For example, the photochromic OSC was firstly proposed by Rene A. J. Janssen et al, whose device exhibited remarkable changes in color under UV light [17]; although a very low PCE below 0.5 % was achieved [18][19].…”