Development of the Multi-wavelength LED Lamp to Improve Plant Growth

Light-emitting diodes (LEDs) based on semiconductor compounds InGaN, GaAsP, and their solid solutions are actively used in devices for artificial illumination of plants - phytolamps. Their advantages are the ability of obtaining radiation in the entire visible range, high efficiency and low energy consumption. A multi-wavelength phytolamp based on InGaN and GaAsP LEDs with an adjustable spectral composition of radiation was developed. The spectral and energy characteristics were measured and the photosynthetic photon flux density was calculated for each type of LED. The dependencies of the active region heating of blue and red LEDs were obtained by the method of determining the temperature from the shift of the luminescence spectrum in order to take into account the degradation of LED structures to correctly choose the device design. The use of the experimentally created phytolamp showed an improvement in the characteristics of plant development, such as germination, average root length, the appearance of primary and secondary leaves by an average of 3 times for basil, and 1.7 times for lemon balm.