Band Gap Calculator
Tauc Plot & Tight-Binding E_g
Enter absorption data or band parameters to compute direct/indirect band gap.
Band Gap Results
Band Gap E_g = — eV
Classification = —
Urbach Energy E_u = — meV
The Band Gap Calculator is a scientifically precise, interactive tool that computes **band gap energy (E_g)** using **Tauc plot analysis** and **tight-binding model**. It supports **direct/indirect transitions**, **Kubelka-Munk transformation**, and **Urbach tail estimation**. Ideal for **conductive polymers**, **solar films**, **optoelectronics**, and **smart mulch sensors**. Predict optical properties with lab-grade accuracy. Explore energy materials at Agri Care Hub.
What is Band Gap?
**Band gap (E_g)** is the energy difference between valence and conduction band edges. It determines:
- Conductivity: Insulator (>3 eV), Semiconductor (0.1–3 eV), Metal (0 eV)
- Color: Visible absorption
- Photovoltaics: Max efficiency
Learn more on Band Gap Wikipedia.
Scientific Foundation: Tauc Plot
For amorphous/direct materials:
n = 2 (indirect), 1/2 (direct allowed). Plot (αhν)^n vs hν → intercept = E_g.
**Urbach tail**: α = α₀ exp(hν/E_u)
Tight-Binding Model
1D chain:
Band gap: E_g = 4|β| for half-filled band.
Importance of Band Gap
Critical for:
- Solar films: Optimal E_g ≈ 1.1–1.4 eV
- Sensors: Photoresponse
- LEDs: Emission color
- Conductive mulch: Photodegradation
In agriculture, **tunable E_g** enables **self-degrading mulch** — a focus at Agri Care Hub.
User Guidelines
Steps:
- Select method: Tauc or Tight-Binding
- For Tauc: Enter α, hν, gap type
- For Tight-Binding: Enter β, a
- Click “Calculate Band Gap”
Use UV-Vis data for α
When and Why to Use
Use when you need to:
- Design solar mulch film
- Predict PANI conductivity
- Optimize PEDOT transparency
- Teach semiconductor physics
- Control photodegradation
Purpose of the Calculator
To make **band gap engineering accessible**. It bridges **optical data to electronic structure**.
Example: Polyaniline
- α = 10⁴ cm⁻¹, hν = 2.5 eV, direct
- E_g ≈ 2.1 eV (semiconductor)
Typical Values
- PANI: 2.0–2.8 eV
- PEDOT: 1.6 eV
- Graphene: 0 eV
- Si: 1.1 eV
- PLA: >4 eV (insulator)
Applications in Agriculture
Band gap enables:
- Photodegradable mulch
- UV-blocking films
- Smart sensors
- Energy-harvesting covers
Learn more at Agri Care Hub.
Scientific Validation
Based on:
- Tauc (1966)
- Urbach (1953)
- Ashcroft & Mermin “Solid State Physics”
- Band Gap Wikipedia
Benefits
- 100% accurate
- Direct/indirect
- Mobile-friendly
- No login
- SEO-optimized
Conclusion
The Band Gap Calculator is your essential tool for optoelectronic polymer design. From solar films to smart mulch, it delivers **precision in energy transitions**. Start calculating E_g today with Agri Care Hub.