NTHU Develops World's Brightest Room-Temperature Single-Photon Source; Application Expected Within 5 Years

(Central News Agency, reporter Hsu Wei-chih, Taipei, 10th) A research team led by Professor Hao-Wu Lin from National Tsing Hua University's Department of Materials Science and Engineering has developed the world's brightest, fastest, and non-flickering single-photon source that operates at room temperature, emitting over 2.3 billion photons per second, setting a new world record. Applications in quantum encrypted communication are expected within 5 years.

Professor Lin explained that traditional semiconductor single-photon sources require operation in low-temperature environments near absolute zero, but perovskite quantum dots can emit light stably at room temperature, significantly reducing equipment costs and application barriers. The brightness of the device developed by the team exceeds existing international records by more than 10 times. It is expected to be applied to quantum encrypted communication within 5 years and could become a core component of quantum computers within 5 to 10 years.

National Tsing Hua University issued a press release today stating that quantum technology is seen as a key technology that could rewrite the global technological landscape, triggering strategic competition among nations in communications, computing, and sensing. Taiwan has also actively invested in the independent development of core components in recent years. These applications all rely on single-photon sources that emit "only one photon at a time."

Professor Lin explained that the brightness of this type of light source directly determines the data transmission speed; the brighter it is, the faster the transmission. However, simultaneously achieving high brightness, fast emission, and stable non-flickering at room temperature has been one of the most difficult challenges in the global quantum optoelectronics field.

The NTHU research team combined perovskite quantum dots with silver nanocubes approximately 100 nanometers in size to construct a "plasmonic nanocavity," enabling strong interaction between light and matter. The biggest challenge was that the two materials were originally "incompatible," because silver nanocubes need to be immersed in highly polar solvents like alcohol, but traditional perovskite quantum dots dissolve and lose their luminescence when exposed to such solvents.

The first author of the paper, doctoral student Tzu-Hao Liao from the Institute of Materials Science and Engineering at NTHU, stated that the team used special "zwitterionic" ligands to coat the quantum dots, like putting on a "nano raincoat" that defends against damage from polar solvents like alcohol while successfully maintaining the quantum dots' luminescence efficiency of up to 95%.

Co-author of the paper, Dr. Yung-Tang Chuang from the same institute, mentioned that the "Purcell effect" generated by combining quantum dots with the cavity significantly increases the emission rate by 435 times, shortens the emission lifetime to below 12 picoseconds, and increases the overall emission intensity by 250 times compared to before integration. (Editor: Huang Mingxi) 1150610