This article presents a breakthrough in the development of perovskite light-emitting diodes (PeLEDs) for active-matrix displays, achieving microsecond response times and high external quantum efficiencies. The key innovation is the use of an individual-particle passivation strategy, where BF₄⁻ ions are used to passivate every nanocrystal in the perovskite emissive layer during film deposition. This results in a defect-free film with discrete nanostructure and excellent crystallinity, which inhibits ion migration. The strategy is applied to perovskite nanocrystal films with different colors: red (635 nm), green (520 nm), and blue (475 nm). These PeLEDs demonstrate response times within microseconds and high external quantum efficiencies of 22.7%, 26.2%, and 18.1%, respectively. This allows the creation of microsecond-response active-matrix PeLEDs with external quantum efficiencies above 20% at a display brightness of 500–3,000 cd m⁻² for green devices with a resolution of 30 pixels per inch. The study also develops microsecond-response red, green, and blue active-matrix displays with 90 pixels per inch. Active-matrix (AM) displays are self-emissive devices where each pixel of a light-emitting diode (LED) is independently controlled using thin-film transistor (TFT) circuits. Compared to conventional liquid-crystal displays, AM electroluminescent devices have a simplified structure, lower power consumption, wider view angle, and higher contrast. In AM displays, the screen refresh rate requires LEDs with a fast response time; the time from the onset of the pulse voltage until steady electroluminescence (EL) of LEDs (typically 90% of the final value) should be less than a millisecond when the refresh rate increases to 120 Hz or higher frequency. Metal halide perovskite LEDs (PeLEDs) are attractive for AM displays due to their high colour purity, efficiency, growing operational stability, and potential for cost-effective fabrication of large-area panels. The peak external quantum efficiencies (EQEs) of prototype infrared-red, green, and sky-blue emissive PeLEDs are approaching the theoretical limit and the operational stability has reached 520 h at 1,000 cd m⁻² for green-emitting devices. However, their EL response under pulsed operation has been largely overlooked. The response time of a PeLED has been decreased by reducing interfacial capacitance and resistance. Nevertheless, the typical transient EL of PeLEDs shows two regions: an initial fast rise (in the range of microseconds) upon application of the pulse voltage, followed by a slow rise (in the range of tens of milliseconds) before reaching the steady EL. The slow rise in the range of tensThis article presents a breakthrough in the development of perovskite light-emitting diodes (PeLEDs) for active-matrix displays, achieving microsecond response times and high external quantum efficiencies. The key innovation is the use of an individual-particle passivation strategy, where BF₄⁻ ions are used to passivate every nanocrystal in the perovskite emissive layer during film deposition. This results in a defect-free film with discrete nanostructure and excellent crystallinity, which inhibits ion migration. The strategy is applied to perovskite nanocrystal films with different colors: red (635 nm), green (520 nm), and blue (475 nm). These PeLEDs demonstrate response times within microseconds and high external quantum efficiencies of 22.7%, 26.2%, and 18.1%, respectively. This allows the creation of microsecond-response active-matrix PeLEDs with external quantum efficiencies above 20% at a display brightness of 500–3,000 cd m⁻² for green devices with a resolution of 30 pixels per inch. The study also develops microsecond-response red, green, and blue active-matrix displays with 90 pixels per inch. Active-matrix (AM) displays are self-emissive devices where each pixel of a light-emitting diode (LED) is independently controlled using thin-film transistor (TFT) circuits. Compared to conventional liquid-crystal displays, AM electroluminescent devices have a simplified structure, lower power consumption, wider view angle, and higher contrast. In AM displays, the screen refresh rate requires LEDs with a fast response time; the time from the onset of the pulse voltage until steady electroluminescence (EL) of LEDs (typically 90% of the final value) should be less than a millisecond when the refresh rate increases to 120 Hz or higher frequency. Metal halide perovskite LEDs (PeLEDs) are attractive for AM displays due to their high colour purity, efficiency, growing operational stability, and potential for cost-effective fabrication of large-area panels. The peak external quantum efficiencies (EQEs) of prototype infrared-red, green, and sky-blue emissive PeLEDs are approaching the theoretical limit and the operational stability has reached 520 h at 1,000 cd m⁻² for green-emitting devices. However, their EL response under pulsed operation has been largely overlooked. The response time of a PeLED has been decreased by reducing interfacial capacitance and resistance. Nevertheless, the typical transient EL of PeLEDs shows two regions: an initial fast rise (in the range of microseconds) upon application of the pulse voltage, followed by a slow rise (in the range of tens of milliseconds) before reaching the steady EL. The slow rise in the range of tens