Cesium
lead halide perovskite nanocrystals have recently become
emerging materials for color conversion in visible light communication
(VLC) and solid-state lighting (SSL), due to their fast response and
desirable optical properties. Herein, perovskite nanocrystal-polymethyl
methacrylate (PNC-PMMA) films with red and yellow emission are prepared.
The PNC-PMMA films, with optical properties such as a short lifetime
and air stability, are used to make broadband color converters based
on a high-bandwidth 75 μm blue micro-LED (μLED) for VLC.
The yellow-emitting CsPb(Br/I)3 PNC-PMMA has a high bandwidth
of 347 MHz, while the red-emitting CsPbI3 PNC-PMMA exhibits
a higher modulation bandwidth of 822 MHz, which is ∼65 times
larger than that of conventional phosphors. After fixing the two PNC-PMMA
films in front of the μLED, a qualified warm white light is
generated with a correlated color temperature of 5670 K, a color rendering
index of 75.7, and a de L’Eclairage (CIE) coordinate at (0.33,
0.35). Although the color conversion of the blue light sacrifices
some received power and slightly reduces the overall bandwidth from
1.130 to 1.005 GHz, a maximum real-time data rate of 1.7 Gbps is still
achievable using the non-return-to-zero on–off keying modulation
scheme, which is ∼6 times higher than that of the previous
record. This study provides a practical approach to develop a considerably
high-bandwidth white-light system for both high-speed VLC and high-quality
SSL.
The data rate of a visible light communication (VLC) system is basically determined by the electrical-to-optical (E-O) bandwidth of its light-emitting diode (LED) source. In order to break through the intrinsic limitation of the carrier recombination rate on E-O bandwidth in conventional c-plane LEDs based on InGaN quantum wells, a blue micro-LED with an active region of nano-structured InGaN wetting layer is designed, fabricated, and packaged to realize a high-speed VLC system. The E-O bandwidth of the micro-LED can reach up to 1.3 GHz. Based on this high-speed micro-LED, we demonstrated a data rate of 2 Gbps with a bit error rate (BER) of
1.2
×
10
−
3
with simple on-off keying signal for a 3-m real-time VLC. In addition, a 4-Gbps VLC system using quadrature phase shift keying-orthogonal frequency-division multiplexing with a BER of
3.2
×
10
−
3
is also achieved for the same scenario. Among all the point-to-point VLC systems based on a single-pixel LED, this work has the highest distance-bandwidth product of 3 GHz·m and the highest distance-rate product of 12 Gbps·m.
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