Submitted by Valerie Ding on Wed, 01/01/2014 - 6:31pm
Each algorithm was implemented in JAVA programs. First, raw NASA solar spectrum data was read into the program as a XLSX file and data-mapped into a TreeMap, an ordered organizational structure in JAVA. The Solar Spectrum and Photon Flux algorithms were implemented and programmed to prepare the data for future computation. Then, absorption spectra, quantum mechanically cloud-computed beforehand for each quantum dot diameter (1 nanometer to 5 nanometers, in increments of 0.5 nanometers), were read into the program as TXT files and data-mapped into a separate TreeMap. Each of the photon-layer algorithms were implemented as methods (functions) in JAVA, to be executed as appropriate during each computational run. The total number of incoming photons from the Sun was set to 10,000,000 (10 millions) because had the number been set smaller, the outcomes would be more likely to be unrepresentative and random, and had the number been set larger, computation would be too heavy to be viable. From there, the programs utilized probabilistic Monte Carlo simulation and the developed algorithms to compute output spectra for each quantum dot stack of multijunction quantum dot solar cells that could be analyzed for absorption and conversion statistics. In successive runs, stack permutations were computed and tested by utilizing former output spectra as input spectra, so as to superimpose the absorption of the added stack over that of the prior. Solar cell thickness was a control and set to 18 microns across all mono- and multi-stack designs (9 stacks of 2 microns each), due to reasoning that all efficiency comparisons needed to be on the basis of stack-combination differences rather than varying thickness. Finally, an interactive user interface was programmed with JAVA graphical tools, streamlining the testing process. The end result was a collection of TXT output files for each quantum dot stack permutation forming the basis for novel multijunction quantum dot solar cell designs, which were all programmed to automatically be saved in a data folder and could then be opened as XLSX files and analyzed.