Journal of the American Chemical Society, Vol.141, No.6, 2623-2629, 2019
Two-Dimensional Hybrid Perovskite-Type Ferroelectric for Highly Polarization-Sensitive Shortwave Photodetection
Two-dimensional (2D) materials have been well developed for polarization-sensitive photodetection, while new 2D members used in shortwave region (>2.5 eV) still remain scarce. The family of 2D hybrid perovskite ferroelectrics, in which the coupling of spontaneous polarization (P-s) and light benefits dissociation of photoinduced carriers, has shown great potential in this portfolio. Here, we report a new 2D hybrid perovskite ferroelectric, [CH3(CH2)(3)NH3](2)(CH3NH3)Pb2Br7 (1), which exhibits a superior P-s of 3.6 mu C/cm(2) and a relatively wide bandgap (similar to 2.55 eV). The unique 2D perovskite motif results in an intrinsic anisotropy of optical absorption (the ratio alpha(c)/alpha(a) approximate to 1.9 at 405 nm), involving its polarization sensitive activity. As expected, the strongest photoresponses were observed along the c-axis (i.e., parallel to 13,), along with a large dichroism ratio (I-ph(c)/I-ph(a) approximate to 2.0) and highly sensitive detectivity up to similar to 10(9) Jones. Further, crystal-device of 1 shows a fast responding rate (similar to 20 mu s) and excellent antifatigued merits. As pioneering work, 1 is the first polarization-sensitive ferroelectric in the new branch of 2D hybrid perovskites. Such intriguing behaviors make 1 a potential candidate for the shortwave polarized-light detection, which also sheds light on new functionalities for future optoelectronic application of hybrid perovskites.