This is rather a broad question depending on whether your research interest is focused on accounting, sustainability, public policy, business strategy, business ethics, etc. However, a few references are provided below:
Dixon-Fowler, H. R., Slater, D. J., Johnson, J. L., Ellstrand, A. E., & Romi, A. M. (2013). Beyond “does it pay to be green?” A meta-analysis of moderators of the CEP–CFP relationship. Journal of Business Ethics, 112(2), 353-366.
Qiu, Y., Shaukat, A., & Tharyan, R. (2016). Environmental and social disclosures: Link with corporate financial performance. The British Accounting Review, 48(1), 102-116.
Barbu, E. M., Dumontier, P., Feleagă, N., & Feleagă, L. (2014). Mandatory environmental disclosures by companies complying with IASs/IFRSs: The cases of France, Germany, and the UK. The International Journal of Accounting, 49(2), 231-247.
Plumlee, M., Brown, D., Hayes, R. M., & Marshall, R. S. (2015). Voluntary environmental disclosure quality and firm value: Further evidence. Journal of Accounting and Public Policy, 34(4), 336-361.
Lyon, T. P., & Shimshack, J. P. (2015). Environmental disclosure: Evidence from Newsweek’s green companies rankings. Business & Society, 54(5), 632-675.
Heflin, F., & Wallace, D. (2017). The BP oil spill: shareholder wealth effects and environmental disclosures. Journal of Business Finance & Accounting.
Lewis, B. W., Walls, J. L., & Dowell, G. W. (2014). Difference in degrees: CEO characteristics and firm environmental disclosure. Strategic Management Journal, 35(5), 712-722.
Cormier, D., & Magnan, M. (2015). The economic relevance of environmental disclosure and its impact on corporate legitimacy: An empirical investigation. Business Strategy and the Environment, 24(6), 431-450.
Meng, X. H., Zeng, S. X., Shi, J. J., Qi, G. Y., & Zhang, Z. B. (2014). The relationship between corporate environmental performance and environmental disclosure: An empirical study in China. Journal of environmental management, 145, 357-367.
Your question may be broken down into two sub-questions:
- is it about what firms disclose or how much they disclose?
The literature is rather about how much they disclose, and why they disclose. The two bodies of literature are the accounting perspective and the organizational behavior perspective. They are quite different but I'd say that the accounting perspective might be what you're looking for. Go for a search in Accounting, Organizations and Society, lots of materials there.