Copper-based Perovskites with Horizontal Transition Dipole Moment for Highly Efficient Light-emitting Diodes
Lead Research Organisation:
University of Cambridge
Department Name: Chemical Engineering and Biotechnology
Abstract
Halide perovskites are poised to revolutionize the LEDs display technology for their extraordinary optoelectronic properties, such as
high colour purity, easy solution processibility, nearly 100% photoluminescence quantum yield (PLQY), and broad light emission
tunability. However, to realize the practical applications of perovskite LEDs in display and lighting technology, some key issues, such
as the presence of toxic lead in most emissive perovskites and the weak stability of typical perovskite LEDs, must be solved. Copper-based
perovskites, especially the blue emissive Cs3Cu2I5, are one of the most promising lead-free perovskite families for their low
toxicity, remarkable PLQY, and excellent stability. Nevertheless, the record external quantum efficiency (EQE) of Cs3Cu2I5 blue LEDs is
only 1.12%. In this proposal, we will improve the light outcoupling efficiency of copper-based perovskite LEDs by controlling the
transition dipole moment orientation of the emissive layers. Copper-based perovskite thin films with dominated horizontal transition
dipole moments will be fabricated by synthesizing their ultrathin nanoplates and assembling these nanoplates into thin films.
Copper-based perovskite LEDs with these thin films as emissive layers will be manufactured and theoretically investigated with the
finite-difference time-domain (FDTD) method. By doing so, we aim to break the record for the EQE of copper-based perovskite LEDs
with an EQE surpassing 10% in blue LEDs and surpassing 4% in white LEDs.
high colour purity, easy solution processibility, nearly 100% photoluminescence quantum yield (PLQY), and broad light emission
tunability. However, to realize the practical applications of perovskite LEDs in display and lighting technology, some key issues, such
as the presence of toxic lead in most emissive perovskites and the weak stability of typical perovskite LEDs, must be solved. Copper-based
perovskites, especially the blue emissive Cs3Cu2I5, are one of the most promising lead-free perovskite families for their low
toxicity, remarkable PLQY, and excellent stability. Nevertheless, the record external quantum efficiency (EQE) of Cs3Cu2I5 blue LEDs is
only 1.12%. In this proposal, we will improve the light outcoupling efficiency of copper-based perovskite LEDs by controlling the
transition dipole moment orientation of the emissive layers. Copper-based perovskite thin films with dominated horizontal transition
dipole moments will be fabricated by synthesizing their ultrathin nanoplates and assembling these nanoplates into thin films.
Copper-based perovskite LEDs with these thin films as emissive layers will be manufactured and theoretically investigated with the
finite-difference time-domain (FDTD) method. By doing so, we aim to break the record for the EQE of copper-based perovskite LEDs
with an EQE surpassing 10% in blue LEDs and surpassing 4% in white LEDs.
| Description | Perovskite light-emitting diodes are promising for next-generation display and lighting applications. However, the performance of perovskite blue light-emitting diodes lags behind their green and red counterparts. In this project, we have investigated perovskite-based blue emitters for light-emitting diode applications. We have discovered that the full width at half maximum of perovskite blue emitters is markedly dependent on the substrates used for the fabrication of perovskite films. This knowledge has been neglected before, but it is essential for achieving narrowband perovskite blue light-emitting diodes. Based on this understanding, we have demonstrated perovskite blue light-emitting diodes with ultrahigh color purity. In addition, we have identified that one of the main reasons for the low performance of perovskite blue light-emitting diodes is their inferior light outcoupling efficiency. We have developed a methodology to improve the device light outcoupling. By doing so, we have demonstrated perovskite blue light-emitting diodes with a new record external quantum efficiency. More importantly, this methodology is applicable for perovskite sky-blue, pure-blue, and deep-blue light-emitting diodes. |
| Exploitation Route | These findings are expected to improve our fundamental understanding of perovskite blue emitters and speed up their practical application of perovskite light-emitting diodes in display and lighting technologies. It will be relevant for emerging lighting/display companies, including startups, who could adopt these material platforms, as well as established lighting and display companies interested in exploring new technologies. |
| Sectors | Digital/Communication/Information Technologies (including Software) Electronics Energy Manufacturing including Industrial Biotechology |