Determination of Planck’s Constant using Light Emitting Diodes

Abstract

Abstract. Planck's constant is named after Max Planck, a nineteenth-century physicist who first described it by relating it as E=h usual meanings. It is a relationship used when comparing a quantum of energy absorbed to that emitted during electron transitions which can be extended to emission by light-emitting diodes. The purpose of this study was to determine Planck's constant using the energy needed to excite free electrons in a light emitting diode. When a light-emitting diode is switched on, electrons recombine with holes within and release energy in the form of photons which can be determined using energy band gaps of the semiconductor composite material used to fabricate the LED. Therefore, LEDs consist of a chip of doped semiconducting layers to create a p-n junction. In LEDs, current flows easily from the p-side to the n-side but not in the reverse from electrodes with different voltages. When an electron meets a hole, it is inhaled and it falls into lower energy level releasing energy in the form of a photon. Photon emissions take place when electrons return to a lower energy state. Therefore, electrons within a LED crystal are excited to a higher energy state and any radiation emitted depends on the p-n junction direct band gap. Depending on the materials used, LEDs emit radiation with energies corresponding to either near-infrared, visible, or near-ultraviolet light. In reality, a LED is designed to have a small area (approximately less than 1 mm 2 ). In this work, an electric current was used to excite electrons and the corresponding energy was measured using a voltmeter. Planck's constant was calculated by substituting the obtained frequency and energy from the voltmeter in the relationship, E = h.

Influence of Different Spherical Binary Plasmonic NPs on HTM Layer in Methyl Ammonium Lead Triiodide Solar Cell

“…It also implies that the fill factor of this solar cell will decrease as thickness increase and the consequence will be that the cell internally consumes power reducing efficiency after a certain peak thickness. Similar observations were re-ported by the experimental result by [16], who concluded that recombination expedites with increasing thickness.…”

“…The material optical parameters used in SCAPS-1D simulation were selectively picked from published articles by [35] and a number of supporting optoelectronic theories. The other optical constant and absorption coefficients for both CH3NH3PbI3 and Ag:CH3NH3PbI3 were obtained from [16]. A summary of some of these optical parameters are as tabulated in tables 1.…”

Algorithm based determination of the Planck’s constant

“…There are numerous methods to determine the Planck's constant [2][3][4][5][6][7][8][9][10][11][12][13]. In the undergraduate laboratories the Planck's constant is experimentally calculated using light emitting diode (LEDs) of different colours.…”

“…Mosiori et al and Eagan [4,14] used a spectrophotometer to find the wavelength of the light being emitted by the LEDs and used these values to experimentally find the Planck's constant. Nieves et al [10] used a monochromator to determine the respective wavelengths of the light emitted by the LEDs.…”