Enhanced Piezoelectricity of MAPbI3 by the Introduction of MXene and Its Utilization in Boosting High‐Performance Photodetectors

Recently, perovskite photodetectors (PDs) are risen to prominence due to substantial research interest. Beyond merely tweaking the composition of materials, a cutting‐edge advancement lies in leveraging the innate piezoelectric polarization properties of perovskites themselves. Here, the investigation shows utilizing Ti3C2Tx, a typical MXene, as an intermediate layer for significantly boosting the piezoelectric property of MAPbI3 thin films. This improvement is primarily attributed to the enhanced polarization of the methylammonium (MA+) groups within MAPbI3, induced by the OH groups present in Ti3C2Tx. A flexible PD based on the MAPbI3/MXene heterostructure is then fabricated. The new device is sensitive to a wide range of wavelengths, displays greatly enhanced performance owing to the piezo‐phototronic coupling. Moreover, the device is endowed with a greatly reduced response time, down to millisecond level, through the pyro‐phototronic effect. The characterization shows applying a −1.2% compressive strain on the PD leads to a remarkable 102% increase in the common photocurrent, and a 76% increase in the pyro‐phototronic current. The present work reveals how the emerging piezo‐phototronic and pyro‐phototronic effects can be employed to design high‐performance flexible perovskite PDs. This research details a strategy to boost the piezoelectric performance of MAPbI3 by using a MXene substrate. It is demonstrated that the surface OH groups on the MXene induce a stronger polarization of the MA+ ions in the MAPbI3 compared to that of the O and F groups, leading to a much more enhanced piezoelectric effect. An innovative type of flexible photodetector (PD) based on a piezoelectric MXene/MAPbI3 heterostructure is crafted, which can be enhanced simultaneously by the piezo‐phototronic and pyro‐phototronic effects. Utilizing MXene to boost the piezoelectricity of MAPbI3 reveals wide‐range potentials for future optoelectronic applications.