Recent Advances in Flexible Perovskite Light‐Emitting Diodes

Abstract

Figure 7. a) Synthesis, etching and transfer processes for the large scale and patterned graphene films. Reproduced with permission. [81] Copyright 2009, Macmillan Publishers Limited. b) Schematic illustration of the procedures to prepare stretchable SWCNT/PDMS films. Reproduced with permission. [85] Copyright 2012, Wiley-VCH. c) Schematic diagram of the hybrid graphene-AgNW-polymer electrode preparation. Reproduced with permission. [93a]

Flexible perovskite light-emitting diodes: Progress, challenges and perspective

“…The energy level data for the most common materials used as ETLs, HTLs, and perovskite emission layers are summarized in Fig. 3b [13,44,45].…”

“…As mentioned in the INTRODUCTION section, the EQE could be calculated with the formula EQE = IQE × η oc , where η oc is the light outcoupling efficiency [65,109]. However, not all the generated photons can be emitted into free space, as they might be captured by emitting materials, electrodes, and substrates [13,78]. Since the IQE which could be estimated from PLQYs has already approached unity, improving the light outcoupling efficiency has become the most critical factor to further improving the device performance [78,110,111].…”

“…Metals (e.g., Ag, gold (Au), aluminum (Al), and copper (Cu)) have been widely used as flexible electrodes in the field of flexible optoelectronic devices due to their high electrical conductivity, good mechanical flexibility, and robustness [13]. AgNWs are the most used flexible electrode materials.…”

“…So far, the external quantum efficiencies (EQEs) of rigid PeLEDs have recorded 28.1% and 22.2% for green and near-infrared (NIR) PeLEDs, respectively [11,12], which are comparable to conventional organic LEDs (OLEDs). However, rigid PeLEDs are incompatible with the demand for flexible electronics due to their weaknesses of rigidity, fragility, and heavy-weight [13].…”

Soft Polymer–Organolead Halide Perovskite Films for Highly Stretchable and Durable Photodetectors with Pt–Au Nanochain-Based Electrodes

“…The development of stretchable optoelectronic devices with high-performance organic–inorganic materials such as methylammonium lead iodide (MAPbI 3 ) is challenging owing to their rigid and brittle nature. − Therefore, strategies are being actively researched to enable such stretchable devices as they will provide a combination of high performance with low form factor and flexibility of function. − Their direct application is in fields such as solar cells, light-emitting diodes (LEDs), next-generation displays, and photodetectors. − Designing a stable perovskite-based stretchable device mandates meeting two basic requirements: (1) a photosensitive perovskite layer capable of enduring strain due to stretching without degrading in ambient atmosphere and (2) a mechanically durable and highly conductive underlying electrode. , In addition, the fatigue-driven degradation of the perovskite layer during repeated deformations must be limited for the long-term practical viability of such stretchable optoelectronic devices. , Most of the past research work has been limited to bendable perovskite devices, and little success has been achieved in making stable and stretchable perovskite devices. − The challenge has primarily been due to the limited mechanical durability of the devices, lasting only a few hundred stretching cycles under small strains, combined with poor environmental stability. − Therefore, there is an urgent need to address these issues to utilize the excellent electro-optical properties of perovskites for the development of stretchable devices.…”