Fig. 1: Red/NIR-emitting OLEDs for VLC.

a Simplified block diagram of the real-time experimental VLC setup including pulse shaping p(n) and matched filtering p(−n) (where n is the current discrete time sample) using a square-root raised cosine, as defined in ref. ¹⁰. Acronyms are defined as follows: USRP-RIO, Universal Software Radio Peripheral–(with) reconfigurable input/output, emulating data traffic in the on–off keying transmission mode at the transmitter (2953) and the receiver (2943); D_s data source, N_ss number of samples per symbol, LFTX/RX low-frequency transmitter/receiver, DAC digital-to-analogue converter, PD ThorLabs PDA36A-2 silicon detector, ADC analogue-to-digital converter, Sync synchronisation, DOWN down-sampling, E_s estimated data source, OLED organic light-emitting diode. b ITO/PEDOT:PSS/F8BT:eDPP/Ca/Al OLED architecture, including an indium tin oxide (ITO) patterned substrate (anode), a poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) hole-transport layer, an F8BT:eDPP red/NIR-emitting layer, calcium/aluminium (Ca/Al, cathode) and electrode connection legs. c Band diagram for the materials employed in the OLEDs³³. d Molecular structure of the far-red/NIR-emitting π-extended DPP (eDPP). e Molecular structure of the F8BT host matrix