Glass substrate for solar cell

1. A glass substrate for a solar cell, which has a glass composition comprising, in terms of mass %, 50 to 80% of SiO 2 , 5 to 20% of Al 2 O 3 , 0 to 20% of B 2 O 3 , 0 to 20% of MgO, 0 to 20% of CaO, 0 to 20% of SrO, 0 to 20% of BaO, 0.001 to 2% of SnO 2 , 0 to 0.1% of Sb 2 O 3 , and 1 to 500 ppm of Fe 2 O 3 , has a mass ratio SnO 2 /(Fe 2 O 3 +SnO 2 ) of 0.95 or more, and has a difference between transmittances at a wavelength of 400 nm before and after irradiation with ultraviolet ray of 2% or less.

2. A glass substrate for a solar cell according to claim 1 , wherein the glass composition further comprises 0 to 1% of As 2 O 3 .

3. A glass substrate for a solar cell according to claim 1 , which has a glass composition comprising, in terms of mass %, 0 to 20% of a total amount of Li 2 O, Na 2 O, and K 2 O.

4. A glass substrate for a solar cell according to claim 1 , which is substantially free of As 2 O 3 .

5. A glass substrate for a solar cell according to claim 1 , which has a transmittance of 90% or more at a plate thickness of 0.7 mm and at a wavelength of 400 nm to 1,000 nm.

6. A glass substrate for a solar cell according to claim 1 , which has a density of 2.8 g/cm 3 or less.

7. A glass substrate for a solar cell according to claim 1 , which has a thermal expansion coefficient at 30 to 380° C. of 37 to 100×10 −7 /° C.

8. A glass substrate for a solar cell according to claim 1 , which has a strain point of 500° C. or higher.

9. A glass substrate for a solar cell according to claim 1 , which has a liquidus viscosity of 10 4.0 dPa·s or more.

10. A glass substrate for a solar cell according to claim 1 , which has a Young's modulus of 68 GPa or more.

11. A glass substrate for a solar cell according to claim 1 , which is formed by an overflow down draw method.