The development of perovskite light-emitting diodes (PeLEDs) has significantly impacted various fields due to their remarkable optical properties and low-cost fabrication methods. Initially revolutionizing solar cell technology, PeLEDs are now showing immense promise in creating efficient light sources for applications such as next-generation displays, general-purpose lighting, and optical communications. Their narrow emission width, widely tunable bandgap, and solution-processability under ambient conditions offer significant advantages over traditional semiconductor LEDs. The solution-processability allows for easy integration with complementary metal-oxide semiconductors and simplifies the manufacturing process, leading to lower costs. Furthermore, life cycle assessments suggest reduced energy payback time and greenhouse gas emissions compared to silicon-based counterparts, making PeLEDs a more sustainable option. The field of quantum information processing relies heavily on technological advancements in other scientific disciplines. While the potential of quantum systems for information processing has been recognized for decades, it's only recently that experimental demonstrations of quantum advantages in computing and conclusive non-locality tests have been achieved. Progress in photonic quantum technologies, including highly efficient single-photon detectors, integrated photonic circuits, and advanced optical fiber designs, continues to drive new applications. Although some preliminary studies have explored the use of perovskite devices in quantum optics, their application in a complete quantum information processing task has remained elusive until now. This research explores the use of a metal-halide PeLED as a novel light source for a quantum random number generator (QRNG), offering a departure from conventional solid-state light sources used in quantum technologies. Quantum random number generation, based on the inherent randomness of quantum measurements, is crucial for applications like encryption, online gaming, and simulations. This study leverages the PeLED to generate high-quality random numbers from projective measurements on weak coherent polarization states, which are then rigorously certified using the National Institute of Standards and Technology (NIST) randomness test suite and the measurement-device-independent (MDI) approach. The MDI approach is critical for enhancing security as it certifies the privacy of randomness even if the detectors are compromised by an eavesdropper, addressing a major vulnerability in quantum technologies. The successful demonstration of PeLEDs in this context paves the way for future developments in quantum technologies using perovskite light sources.

The generation of random numbers from quantum systems has a rich history, with various approaches aimed at achieving both high-speed generation and robust security. Commercial random number generators often rely on the inherent complexity of certain processes, but this is insufficient for cryptographic applications requiring certified privacy against eavesdropping with infinite computational power and knowledge of the device's inner workings. Quantum mechanics offers a solution by exploiting the intrinsic randomness of quantum measurements. QRNGs are typically classified based on the assumptions made to guarantee privacy against malicious eavesdroppers. Device-independent (DI) QRNGs offer the highest level of security, guaranteeing private randomness even against an adversary who has built the device. However, DI QRNGs usually have modest generation rates. On the other hand, device-dependent (DD) QRNGs can achieve high rates but require full system characterization. Semi-device-independent (SDI) approaches represent a middle ground, offering increased security compared to DD QRNGs while maintaining higher throughput than DI approaches. Homodyne detection-based QRNGs have also demonstrated ultra-high generation rates in both DD and SDI categories. This work builds upon this existing literature by introducing a novel light source for SDI QRNGs, pushing the boundaries of both speed and security while addressing the need for compact, low-cost, and easily integrable devices.

This study employs a metal-halide PeLED as the light source for a measurement-device-independent (MDI) QRNG. The PeLED structure consists of an indium tin oxide (ITO)-coated glass substrate, with a formamidinium lead iodide perovskite active layer sandwiched between electron and hole transport layers. Additional layers of molybdenum oxide (MoOx) and gold (Au) serve as contact layers, and pimelic acid (PA) is incorporated for stability. Under forward bias, electron-hole recombination efficiently generates photons with a central wavelength of 804 nm and a spectral width of 41.6 nm FWHM, yielding a peak external quantum efficiency of around 18%. The MDI-QRNG experimental setup involves a state preparation device (P) using the PeLED to produce weak coherent states, a liquid crystal waveplate (LCWP) for state selection, and an uncharacterized measurement device (M) comprising a polarizing beam splitter (PBS) and single-photon avalanche detectors (SPADs). The user randomly selects between preparing a randomness generation state (a superposition state) or one of two test states (horizontal and vertical polarizations) to verify the measurement device's integrity. The outcomes from the SPADs, representing '0' or '1', are registered by a field-programmable gate array (FPGA) and streamed to a computer for storage and randomness extraction. Events where neither or both detectors register a photon are discarded to minimize errors. A software-based random number generator determines whether a measurement block is for randomness generation (99% probability) or device testing (1% probability). The randomness extraction process uses a Toeplitz hashing extractor to convert the raw bit sequence into a nearly perfectly uniform sequence. The input sequence is split into subsequences, which are then multiplied by a Toeplitz matrix to generate hashed bits. The Toeplitz matrix is defined using a seed from the raw sequence. The final extracted sequence is obtained by concatenating the results of the matrix multiplications. Randomness assessment employs the NIST 800-22 statistical test suite, a benchmark for certifying randomness. A 5 Gbit sample of the generated sequence is divided into blocks of 1 million bits each, and each block is subjected to the 16 tests in the suite. Each test yields a p-value; values above the confidence level (α = 0.01) indicate that the test is passed. The proportion of passed blocks within each test is then analyzed, with a confidence interval calculated to confirm randomness.

This research achieved a high raw bit generation rate of over 10 Mbit/s, placing the developed QRNG among the best reported in the literature, including commercial devices. This rate was maintained for approximately eight days before a gradual decay due to PeLED degradation, with the device retaining more than half of its initial brightness even after 22 days. The sustained performance highlights the practical potential of PeLED-based QRNGs. The success probabilities for the test states remained stable throughout the experiment, indicating that the privacy certification of the generated random numbers was not affected by the PeLED's gradual degradation. The average success probability (Psuc ≈ 0.97 ± 0.01) translates to a min-entropy (Hmin ≈ 0.71 ± 0.01) representing a high level of certified private randomness against detector side-channel attacks. The generated random bit sequence successfully passed all 16 tests of the NIST randomness test suite, confirming its high quality and suitability for cryptographic applications. The visualization of the sequence as an image demonstrated the random distribution of the bits.

This study successfully demonstrates the feasibility of using PeLEDs as a light source for highly secure and efficient QRNGs. The achieved generation rate surpasses many existing QRNGs, making this approach competitive with commercial devices. The utilization of the MDI protocol strengthens the security against eavesdropping attacks targeting the detectors, a common vulnerability in quantum systems. The long operational lifetime of the PeLED, exceeding 22 days before significant degradation, shows promise for practical applications. The successful passage of the NIST randomness tests validates the quality of the generated random numbers. The overall findings highlight the potential of integrating perovskite-based devices into quantum technologies, particularly considering their sustainable aspects. Future work could focus on improving the long-term stability of the PeLEDs, investigating different perovskite materials for enhanced performance, and exploring further miniaturization for more compact QRNG devices.

This work introduces a novel, highly secure, and efficient QRNG using a perovskite light-emitting diode as its light source. The system achieves a generation rate exceeding 10 Mbit/s, exceeding many reported QRNGs, and successfully passes the NIST randomness test suite. The implementation of the measurement-device-independent protocol safeguards against eavesdropping attacks. This research demonstrates the potential of PeLEDs as a cost-effective and sustainable alternative in quantum technologies. Future studies could investigate different perovskite materials, enhancing PeLED stability, and exploring miniaturization to create even more compact QRNG devices.

While the PeLED demonstrated a relatively long operational lifetime, gradual degradation over time did occur. Further research into improving the long-term stability of the PeLEDs is warranted to extend the operational life of the QRNG. The study utilized a software-based random number generator for selecting between randomness generation and device testing; for highly sensitive applications, a trusted low-rate random number source would be necessary. The MDI approach, while enhancing security, does not completely eliminate all potential side-channel attacks. Finally, the current implementation used a specific type of PeLED; exploring other variations may reveal further enhancements.