Third-order photon correlations to extract single nanocrystal multiexciton properties in solution
Data files
Dec 04, 2024 version files 74.66 GB
Abstract
High flux optical applications require materials with high brightness and color pure emission. Colloidal nanocrystals are solution-processible with tunable, spectrally narrow emission, and high brightness per emitter. Multiexciton emission in colloidal nanocrystals can significantly contribute to the brightness of the emission in high flux optical devices. However, multiexciton emission also has the potential to contribute to emission broadening, which reduces color purity. There is a need to understand and control multiexciton behavior in colloidal nanocrystal. Here we develop a third-order photon correlation technique to characterize the average single nanocrystal triexciton quantum yield and lifetime in a solution-phase experiment. This technique derives from the relationship between the Poissonian probability of nanocrystal photon absorption and the intrinsic probability of nanocrystal photon emission. We validate the theoretical background of this technique by creating a numerical model to simulate the diffusion and emission of many nanocrystals in solution. We show that the average triexciton quantum yield and triexciton lifetime can be extracted in a solution of nanocrystals. This work demonstrates a method to investigate the triexciton optical properties of colloidal nanocrystals. This technique will provide a better understanding of multiexciton emission effects from colloidal nanocrystals integrated into high flux optical devices.
README: Third-order photon correlations to extract single nanocrystal multiexciton properties in solution
https://doi.org/10.5061/dryad.2547d7x1z
Description of the data and file structure
Files are stored in matlab (.mat) format
Folder/File Naming
There are two naming structures: One for the solution triexciton quantum yield data and the other for the solution triexciton lifetime data.
Solution Triexciton Quantum Yield Data
For the solution triexciton quantum yield data, the data is stored in folders with the naming convention 'Photons_jBX_iTX' where j and i correspond to the simulated biexciton and triexciton quantum yield, respectively.
Within each folder, the photon stream is split up into a series of photon stream batches which are named 'Photons_1', 'Photons_2','Photons_3',etc.
Solution Triexciton Lifetime Data
For the solution triexciton lifetime data, the data is stored in folders with the naming convention 'Photons_7p5BX_iTX' where i corresponds to the simulated triexciton lifetime.
Within each folder, the photon is split up by each individual nanocrystal photon stream which are named 'qd_1', 'qd_2',' qd_3', etc.
File Content
Solution Triexciton Quantum Yield Data
Each 'Photons_i' file contains three one-dimensional matlab arrays corresponding to the Channel A, Channel B, and Channel C photon streams to be correlated. The photon stream data is in units of picoseconds. We recommend that the third-order cross-correlations are performed on each photon stream batch individually, and then sum the third-order cross-correlations of each batch at the end.
Solution Triexciton Lifetime Data
Each 'qd_i' file contains one two-dimensional matlab array. The first column corresponds to the detection time of the event (in seconds) and the second column corresponds to the detector the event occurred at (0 = excitation time, 1 = Channel A, 2 = Channel B, 3 = Channel C, 4 = Channel D'). We recommend each 'qd_i' file is combined into one large photon stream to perform the Photon Number Resolved Analysis. Below is a sample code that concatenates all the NC photon streams:
function [chT] = ConcatenatePhotonStream(folderName)
% determine number of files in the folder
numNC = length(dir([[folderName], '/*.mat']));
% initialize the concatenated photon stream array
chT = [];
for ii = 1:numNC
% load in the single NC photon stream
photons = load([folderName '/qd_' num2str(ii) '.mat']).photons;
% add the NC photon stream to the end of the total photon stream array
chT = [chT;photons];
disp([num2str(ii) ' out of ' num2str(num_particles)])
end
% sort the photon stream in time order
chT = sortrows(chT);
% convert the photon stream time from seconds to picoseconds
chT(:,1) = chT(:,1)*1e12;
end