$\mathit{\eta }$	Efficiency
${\mathit{V}}_{\mathit{o}\mathit{c}}$	Open Circuit Voltage
${\mathit{J}}_{\mathit{s}\mathit{c}}$	Short-Circuit Current Density
FF	Fill Factor
HTL	Hole transport Layer
ETL	Electron Transport Layer
DAL	Double Absorber Layer
$\mathit{\lambda }$	Wavelength
$\mathit{p}\left(\mathit{x}\right)$	Position-dependent hole concentration
$\mathit{n}\left(\mathit{x}\right)$	Position-dependent electron concentration
${\mathit{N}}_{\mathit{t}\mathit{r}}{}^{\pm }$	Shallow/bulk carrier concentration
G	Electron–hole pair generation
${\mathit{\lambda }}_{\mathit{m}\mathit{i}\mathit{n}}$	Minimum wavelength
${\mathit{\lambda }}_{\mathit{m}\mathit{a}\mathit{x}}$	Maximum wavelength
${\mathit{T}}_{\mathit{f}\mathit{r}\mathit{o}\mathit{n}\mathit{t}}\left(\mathit{\lambda }\right)$	Transmission at front contact dependent on wavelength
${\mathit{R}}_{\mathit{b}\mathit{a}\mathit{c}\mathit{k}}\left(\mathit{\lambda }\right)$	Reflection at back contact dependent on wavelength
${\mathit{R}}_{\mathit{i}\mathit{n}\mathit{t}}\left(\mathit{\lambda }\right)$	Internal reflection at front contact
D	Layer thickness
${\mathit{E}}_{\mathit{g}}$	Energy bandgap
$\mathit{\alpha }$	Optical absorption
${\mathit{E}}_{\mathit{p}}$	Photon energy
${\mathit{R}}_{\mathit{R}\mathit{A}\mathit{D}}$	Radiative recombination
${\mathit{R}}_{\mathit{A}\mathit{U}\mathit{G}}$	Auger recombination
${\mathit{R}}_{\mathit{S}\mathit{R}\mathit{H}}$	Schokley Read hall recombination
K	Radiative recombination coefficient
${\mathit{C}}_{\mathit{n},\mathit{a}\mathit{u}\mathit{g}}$	Auger–electron recombination coefficient
${\mathit{C}}_{\mathit{p},\mathit{a}\mathit{u}\mathit{g}}$	Auger–hole recombination coefficient
$\mathit{n}$	Electron concentration
$\mathit{p}$	Hole concentration
${\mathit{n}}_{\mathit{i}}$	Intrinsic-carrier concentration
${\mathit{\tau }}_{\mathit{n}}$	Electron-carrier lifetime
${\mathit{\tau }}_{\mathit{p}}$	Hole-carrier lifetime
${\mathit{N}}_{\mathit{t}\mathit{r},\mathit{D}\mathit{A}\mathit{L}}$	Trap density of double absorber layer
${\mathit{E}}_{\mathit{c}}$	Characteristic energy
${\mathit{w}}_{\mathit{g}}$	Width of Gaussian energy distribution
${\mathit{w}}_{\mathit{t}}$	Width of tail-like distribution
${\mathit{N}}_{\mathit{p}\mathit{e}\mathit{a}\mathit{k}}$	Peak density of the distribution
${\mathit{E}}_{\mathit{t}}$	Energy trap level
${\mathit{E}}_{\mathit{i}}$	Intrinsic energy level
$\mathit{S}{\mathit{D}}^{\left(0/+\right)}$	Single-donor defect states
$\mathit{D}{\mathit{D}}^{(0/+/2/+)}$	Double-donor defect states
$\mathit{S}{\mathit{A}}^{\left(-/0\right)}$	Single-acceptor defect states
$\mathit{D}{\mathit{A}}^{\left(2/-/0/-\right)}$	Double-acceptor defect states
${\mathit{N}}_{\mathit{t}\mathit{r},\mathit{H}/\mathit{A}}$	Interface defect density at hole transport layer/absorber layer interface
${\mathit{N}}_{\mathit{t}\mathit{r},\mathit{A}/\mathit{E}}$	Interface defect density at absorber layer/electron transport layer interface