Periodic Reporting for period 1 - LEAP (Electrically Pumped Perovskite Lasers)
Période du rapport: 2022-11-01 au 2025-04-30
Electrically pumped lasers are considered as a holy grail in the field of optoelectronics. Despite the success of lasers based on expensive epitaxially grown semiconductors, low-cost solution-processed semiconductors provide new opportunities to significantly expand the applications of lasers. On one hand, low-cost and scalable deposition can meet increasing demand of using lasers in consumer electronics. On the other hand, solution-processed semiconductors can be easily proceeded into thin films, providing great promise to develop thin-film lasers which are required for highly integrated photonic chips in advanced applications.
A superstar in the family of solution-processed semiconductors is metal halide perovskites, which have shown great success in a range of optoelectronic applications. Especially, recent breakthroughs on optically pumped perovskite lasers and high-performance perovskite light-emitting diodes indicate great potential of developing perovskites into a new generation of materials for electrically pumped lasers.
This project has the ambitious goal to realise solution-processed electrically pumped perovskite lasers. I will take a holistic approach, where novel concepts are proposed to address critical challenges on the development of perovskite lasers. Both type-I and type-II perovskite quantum well heterostructures, which utilise fundamentally different mechanisms to reach low thresholds, will be developed as the gain media. Edge-emitting devices based on these new perovskite gain media will then be coupled into rationally designed cavities for lasing actions. At the core of the research is the synthesis of new perovskite materials, combined with advanced spectroscopic characterizations and device/cavity development. This project makes use of recent advances in perovskite optoelectronics to create a new paradigm for electrically pumped perovskite lasers, and will open up new possibilities to revolutionize the current laser technology.
A superstar in the family of solution-processed semiconductors is metal halide perovskites, which have shown great success in a range of optoelectronic applications. Especially, recent breakthroughs on optically pumped perovskite lasers and high-performance perovskite light-emitting diodes indicate great potential of developing perovskites into a new generation of materials for electrically pumped lasers.
This project has the ambitious goal to realise solution-processed electrically pumped perovskite lasers. I will take a holistic approach, where novel concepts are proposed to address critical challenges on the development of perovskite lasers. Both type-I and type-II perovskite quantum well heterostructures, which utilise fundamentally different mechanisms to reach low thresholds, will be developed as the gain media. Edge-emitting devices based on these new perovskite gain media will then be coupled into rationally designed cavities for lasing actions. At the core of the research is the synthesis of new perovskite materials, combined with advanced spectroscopic characterizations and device/cavity development. This project makes use of recent advances in perovskite optoelectronics to create a new paradigm for electrically pumped perovskite lasers, and will open up new possibilities to revolutionize the current laser technology.
1, We developed tin perovskite light-emitting diodes which can survive high current densities. This was made possible by rational manipulation of p doping in all-inorganic tin perovskites (CsSnI3) by retarding and controlling the crystallization process of perovskite precursors in tin-rich conditions. The resulting light-emitting diodes exhibit a peak emission wavelength at 948 nm, high radiance of 226 W sr−1 m−2 and long operational half-lifetime of 39.5 h at a high constant current density of 100 mA cm−2. Our demonstration of efficient and stable light-emitting diodes operating at high current densities open up opportunities towards electrically pumped lasers. Nature Photonics 18, 170–176 (2024)
2. We demonstrated high-brightness lead perovskite light-emitting diodes. This significant improvement is achieved through the incorporation of electron-withdrawing trifluoroacetate anions into three-dimensional perovskite emitters, resulting in retarded Auger recombination due to a decoupled electron-hole wavefunction. Trifluoroacetate anions can additionally alter the crystallization dynamics and inhibit halide migration, facilitating charge injection balance and improving the tolerance of perovskites under high voltages. As a result, we demonstrated bright perovskite light-emitting diodes, with a peak radiance of 2409 W sr−1 m−2 and negligible current-efficiency roll-off, maintaining high external quantum efficiency over 20% even at current densities as high as 2270 mA cm−2. Our findings shed light on a promising future for perovskite emitters in high-power light-emitting applications, including laser diodes. Nature Communications 16, 927 (2025)
3. Charge-transport layers are essential for achieving electrically pumped perovskite lasers. However, their role in perovskite lasing is not fully understood. We explored the role of charge-transport layers on the lasing actions of perovskite films by investigating the amplified spontaneous emission (ASE) thresholds. A largely reduced ASE threshold and enhanced ASE intensity is demonstrated by introducing an additional hole transport layer poly(triaryl amine) (PTAA). It is shown that the key role of the PTAA layer is to accelerate the hot-carrier cooling process by extracting holes in perovskites. With reduced hot holes, the Auger recombination loss is largely suppressed, resulting in decreased ASE threshold. This argument is further supported by the fact that the ASE threshold can be further reduced from 25.7 to 7.2 µJ cm−2 upon switching the pumping wavelength from 400 to 500 nm to directly avoid excess hot-hole generation. This work exemplifies how to further reduce the ASE threshold with transport layer engineering through hot-hole manipulation. This is critical to maintaining the excellent gain properties of perovskites when integrating them into electrical devices, paving the way for electrically pumped perovskite lasers. Advanced Materials 35, 2300922 (2023)
4. We rationalized high efficiency in perovskite emitting devices through a surfactant-induced effect where the hole concentration at the perovskite surface is enhanced to enable sufficient bimolecular recombination pathways with injected electrons. This effect originates from the additive engineering and is verified by a series of optical and electrical measurements. In addition, surfactant additives that induce an increased hole concentration also significantly improve the luminescence yield, an important parameter for the efficient operation of perovskite diodes. Our results not only provide rational design rules to fabricate high-efficiency perovskite diodes but also present new insights to benefit the design of other perovskite optoelectronic devices. Nature Materials, 24, 778 (2025)
2. We demonstrated high-brightness lead perovskite light-emitting diodes. This significant improvement is achieved through the incorporation of electron-withdrawing trifluoroacetate anions into three-dimensional perovskite emitters, resulting in retarded Auger recombination due to a decoupled electron-hole wavefunction. Trifluoroacetate anions can additionally alter the crystallization dynamics and inhibit halide migration, facilitating charge injection balance and improving the tolerance of perovskites under high voltages. As a result, we demonstrated bright perovskite light-emitting diodes, with a peak radiance of 2409 W sr−1 m−2 and negligible current-efficiency roll-off, maintaining high external quantum efficiency over 20% even at current densities as high as 2270 mA cm−2. Our findings shed light on a promising future for perovskite emitters in high-power light-emitting applications, including laser diodes. Nature Communications 16, 927 (2025)
3. Charge-transport layers are essential for achieving electrically pumped perovskite lasers. However, their role in perovskite lasing is not fully understood. We explored the role of charge-transport layers on the lasing actions of perovskite films by investigating the amplified spontaneous emission (ASE) thresholds. A largely reduced ASE threshold and enhanced ASE intensity is demonstrated by introducing an additional hole transport layer poly(triaryl amine) (PTAA). It is shown that the key role of the PTAA layer is to accelerate the hot-carrier cooling process by extracting holes in perovskites. With reduced hot holes, the Auger recombination loss is largely suppressed, resulting in decreased ASE threshold. This argument is further supported by the fact that the ASE threshold can be further reduced from 25.7 to 7.2 µJ cm−2 upon switching the pumping wavelength from 400 to 500 nm to directly avoid excess hot-hole generation. This work exemplifies how to further reduce the ASE threshold with transport layer engineering through hot-hole manipulation. This is critical to maintaining the excellent gain properties of perovskites when integrating them into electrical devices, paving the way for electrically pumped perovskite lasers. Advanced Materials 35, 2300922 (2023)
4. We rationalized high efficiency in perovskite emitting devices through a surfactant-induced effect where the hole concentration at the perovskite surface is enhanced to enable sufficient bimolecular recombination pathways with injected electrons. This effect originates from the additive engineering and is verified by a series of optical and electrical measurements. In addition, surfactant additives that induce an increased hole concentration also significantly improve the luminescence yield, an important parameter for the efficient operation of perovskite diodes. Our results not only provide rational design rules to fabricate high-efficiency perovskite diodes but also present new insights to benefit the design of other perovskite optoelectronic devices. Nature Materials, 24, 778 (2025)
The community, including myself, is generally concerned about the stability issue of tin-based perovskites. This work published in Nature Photonics 18, 170–176 (2024) demonstrated that, in contract to our previous understanding, tin-based perovskites can survive high current densities, making them a promising candidate for laser diodes.