Official Resources
- Homepage: https://github.com/TovCat/Kujo
- Source Repository: https://github.com/TovCat/Kujo
- License: MIT License
Overview
Kujo is a Python-based software tool designed for analyzing exciton dynamics in organic single crystals. It focuses on calculating exciton couplings and rates using various approximations, enabling the study of singlet fission, triplet fusion, and charge transport in crystalline environments.
Scientific domain: Organic crystals, exciton dynamics, singlet fission, charge transport
Target user community: Materials scientists studying organic semiconductors
Theoretical Methods
- Extended Dipole Model (EDM)
- Point Dipole Model
- Transition density coupling
- Marcus theory rates
- Miller-Abrahams rates
- Exciton hopping rates
Capabilities (CRITICAL)
- Calculation of electronic couplings (J)
- Crystal structure parsing (CIF)
- Neighbor list generation
- Rate calculation for hopping
- Angular dependence analysis
- Switching between coupling models
Sources: GitHub repository
Key Strengths
Crystal Structure Handling:
- Direct support for periodic crystals
- Automatic neighbor identification
- Supercell generation
Coupling Models:
- Flexible choice of approximation
- Cutoff-based model switching
- Atomic transition charges
Python Integration:
- Easy to script
- Integrates with QC output parsing
Inputs & Outputs
-
Input formats:
- CIF crystal files
- QC output (for transition densities)
- Configuration file
-
Output data types:
- Coupling matrices
- Rate matrices
- Neighbor lists
Interfaces & Ecosystem
- Input: Gaussian/ORCA/Q-Chem (via cclib/parsing)
- Language: Python
Advanced Features
Cutoff Handling:
- Distance-dependent model selection
- Optimizes accuracy vs speed
Performance Characteristics
- Speed: Fast (algebraic models)
- Bottleneck: Neighbor search in large supercells
Computational Cost
- Low: Post-processing tool
- QC: Requires monomer calculations first
Limitations & Known Constraints
- Approximation: Relies on electrostatic models or transition densities
- Static: Typical usage is static crystal structure
Comparison with Other Codes
- vs VOTCA: Kujo is lighter, more focused on crystal couplings
- Unique strength: Lightweight crystal exciton analysis
Application Areas
- Singlet Fission: Pentacene, rubrene crystals
- OLEDs: Host material transport
- OFETs: Charge mobility estimates
Best Practices
- Monomer QC: Reliable transition densities
- Cutoffs: Test convergence of J with distance
- Supercell: Ensure sufficient size for long-range interactions
Community and Support
- Open-source MIT
- GitHub repository
Verification & Sources
Primary sources:
- GitHub: https://github.com/TovCat/Kujo
Confidence: VERIFIED - GitHub project
Verification status: ✅ VERIFIED
- Official homepage: ACCESSIBLE
- Source code: OPEN (MIT)
- Specialized strength: Organic crystal exciton couplings